Glossary

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Glossary Entries
Word(s)	Definition	Image	Caption	Link	Source
cell	smallest independently functioning unit of all organisms; in animals, a cell contains cytoplasm, composed of fluid and organelles
organ	functionally distinct structure composed of two or more types of tissues
organ system	group of organs that work together to carry out a particular function
organism	living being that has a cellular structure and that can independently perform all physiologic functions necessary for life
tissue	group of similar or closely related cells that act together to perform a specific function
anabolism	assembly of more complex molecules from simpler molecules
catabolism	breaking down of more complex molecules into simpler molecules
development	changes an organism goes through during its life
differentiation	process by which unspecialized cells become specialized in structure and function
growth	process of increasing in size
metabolism	sum of all of the body’s chemical reactions
renewal	process by which worn-out cells are replaced
reproduction	process by which new organisms are generated
responsiveness	ability of an organisms or a system to adjust to changes in conditions
control center	compares values to their normal range; deviations cause the activation of an effector
effector	organ that can cause a change in a value
negative feedback	homeostatic mechanism that tends to stabilize an upset in the body’s physiological condition by preventing an excessive response to a stimulus, typically as the stimulus is removed
normal range	range of values around the set point that do not cause a reaction by the control center
positive feedback	mechanism that intensifies a change in the body’s physiological condition in response to a stimulus
sensor	(also, receptor) reports a monitored physiological value to the control center
set point	ideal value for a physiological parameter; the level or small range within which a physiological parameter such as blood pressure is stable and optimally healthful, that is, within its parameters of homeostasis
abdominopelvic cavity	division of the anterior (ventral) cavity that houses the abdominal and pelvic viscera
anatomical position	standard reference position used for describing locations and directions on the human body
anterior	describes the front or direction toward the front of the body; also referred to as ventral
anterior cavity	larger body cavity located anterior to the posterior (dorsal) body cavity; includes the serous membrane-lined pleural cavities for the lungs, pericardial cavity for the heart, and peritoneal cavity for the abdominal and pelvic organs; also referred to as ventral cavity
caudal	describes a position below or lower than another part of the body proper; near or toward the tail (in humans, the coccyx, or lowest part of the spinal column); also referred to as inferior
cranial	describes a position above or higher than another part of the body proper; also referred to as superior
cranial cavity	division of the posterior (dorsal) cavity that houses the brain
deep	describes a position farther from the surface of the body
distal	describes a position farther from the point of attachment or the trunk of the body
dorsal	describes the back or direction toward the back of the body; also referred to as posterior
dorsal cavity	posterior body cavity that houses the brain and spinal cord; also referred to the posterior body cavity
frontal plane	two-dimensional, vertical plane that divides the body or organ into anterior and posterior portions
inferior	describes a position below or lower than another part of the body proper; near or toward the tail (in humans, the coccyx, or lowest part of the spinal column); also referred to as caudal
lateral	describes the side or direction toward the side of the body
medial	describes the middle or direction toward the middle of the body
pericardium	sac that encloses the heart
peritoneum	serous membrane that lines the abdominopelvic cavity and covers the organs found there
plane	imaginary two-dimensional surface that passes through the body
pleura	serous membrane that lines the pleural cavity and covers the lungs
posterior	describes the back or direction toward the back of the body; also referred to as dorsal
posterior cavity	posterior body cavity that houses the brain and spinal cord; also referred to as dorsal cavity
prone	face down
proximal	describes a position nearer to the point of attachment or the trunk of the body
sagittal plane	two-dimensional, vertical plane that divides the body or organ into right and left sides
section	in anatomy, a single flat surface of a three-dimensional structure that has been cut through
serous membrane	membrane that covers organs and reduces friction; also referred to as serosa
serosa	membrane that covers organs and reduces friction; also referred to as serous membrane
spinal cavity	division of the dorsal cavity that houses the spinal cord; also referred to as vertebral cavity
superficial	describes a position nearer to the surface of the body
superior	describes a position above or higher than another part of the body proper; also referred to as cranial
supine	face up
thoracic cavity	division of the anterior (ventral) cavity that houses the heart, lungs, esophagus, and trachea
transverse plane	two-dimensional, horizontal plane that divides the body or organ into superior and inferior portions
ventral	describes the front or direction toward the front of the body; also referred to as anterior
ventral cavity	larger body cavity located anterior to the posterior (dorsal) body cavity; includes the serous membrane-lined pleural cavities for the lungs, pericardial cavity for the heart, and peritoneal cavity for the abdominal and pelvic organs; also referred to as anterior body cavity
computed tomography (CT)	medical imaging technique in which a computer-enhanced cross-sectional X-ray image is obtained
magnetic resonance imaging (MRI)	medical imaging technique in which a device generates a magnetic field to obtain detailed sectional images of the internal structures of the body
positron emission tomography (PET)	medical imaging technique in which radiopharmaceuticals are traced to reveal metabolic and physiological functions in tissues
ultrasonography	application of ultrasonic waves to visualize subcutaneous body structures such as tendons and organs
X-ray	form of high energy electromagnetic radiation with a short wavelength capable of penetrating solids and ionizing gases; used in medicine as a diagnostic aid to visualize body structures such as bones
active transport	form of transport across the cell membrane that requires input of cellular energy
amphipathic	describes a molecule that exhibits a difference in polarity between its two ends, resulting in a difference in water solubility
cell membrane	membrane surrounding all animal cells, composed of a lipid bilayer interspersed with various molecules; also known as plasma membrane
channel protein	membrane-spanning protein that has an inner pore which allows the passage of one or more substances
concentration gradient	difference in the concentration of a substance between two regions
diffusion	movement of a substance from an area of higher concentration to one of lower concentration
electrical gradient	difference in the electrical charge (potential) between two regions
endocytosis	import of material into the cell by formation of a membrane-bound vesicle
exocytosis	export of a substance out of a cell by formation of a membrane-bound vesicle
extracellular fluid (ECF)	fluid exterior to cells; includes the interstitial fluid, blood plasma, and fluid found in other reservoirs in the body
facilitated diffusion	diffusion of a substance with the aid of a membrane protein
glycocalyx	coating of sugar molecules that surrounds the cell membrane
glycoprotein	protein that has one or more carbohydrates attached
hydrophilic	describes a substance or structure attracted to water
hydrophobic	describes a substance or structure repelled by water
hypertonic	describes a solution concentration that is higher than a reference concentration
hypotonic	describes a solution concentration that is lower than a reference concentration
integral protein	membrane-associated protein that spans the entire width of the lipid bilayer
interstitial fluid (IF)	fluid in the small spaces between cells not contained within blood vessels
intracellular fluid (ICF)	fluid in the cytosol of cells
isotonic	describes a solution concentration that is the same as a reference concentration
ligand	molecule that binds with specificity to a specific receptor molecule
osmosis	diffusion of molecules down their concentration across a selectively permeable membrane
passive transport	form of transport across the cell membrane that does not require input of cellular energy
peripheral protein	membrane-associated protein that does not span the width of the lipid bilayer, but is attached peripherally to integral proteins, membrane lipids, or other components of the membrane
phagocytosis	endocytosis of large particles
pinocytosis	endocytosis of fluid
receptor	protein molecule that contains a binding site for another specific molecule (called a ligand)
receptor-mediated endocytosis	endocytosis of ligands attached to membrane-bound receptors
selective permeability	feature of any barrier that allows certain substances to cross but excludes others
sodium-potassium pump	(also, Na⁺/K⁺ ATP-ase) membrane-embedded protein pump that uses ATP to move Na⁺ out of a cell and K⁺ into the cell
vesicle	membrane-bound structure that contains materials within or outside of the cell
autolysis	breakdown of cells by their own enzymatic action
autophagy	lysosomal breakdown of a cell’s own components
centriole	small, self-replicating organelle that provides the origin for microtubule growth and moves DNA during cell division
cilia	small appendage on certain cells formed by microtubules and modified for movement of materials across the cellular surface
cytoplasm	internal material between the cell membrane and nucleus of a cell, mainly consisting of a water-based fluid called cytosol, within which are all the other organelles and cellular solute and suspended materials
cytoskeleton	“skeleton” of a cell; formed by rod-like proteins that support the cell’s shape and provide, among other functions, locomotive abilities
cytosol	clear, semi-fluid medium of the cytoplasm, made up mostly of water
endoplasmic reticulum (ER)	cellular organelle that consists of interconnected membrane-bound tubules, which may or may not be associated with ribosomes (rough type or smooth type, respectively)
flagellum	appendage on certain cells formed by microtubules and modified for movement
Golgi apparatus	cellular organelle formed by a series of flattened, membrane-bound sacs that functions in protein modification, tagging, packaging, and transport
intermediate filament	type of cytoskeletal filament made of keratin, characterized by an intermediate thickness, and playing a role in resisting cellular tension
lysosome	membrane-bound cellular organelle originating from the Golgi apparatus and containing digestive enzymes
microfilament	the thinnest of the cytoskeletal filaments; composed of actin subunits that function in muscle contraction and cellular structural support
microtubule	the thickest of the cytoskeletal filaments, composed of tubulin subunits that function in cellular movement and structural support
mitochondrion	one of the cellular organelles bound by a double lipid bilayer that function primarily in the production of cellular energy (ATP)
mutation	change in the nucleotide sequence in a gene within a cell’s DNA
nucleus	cell’s central organelle; contains the cell’s DNA
organelle	any of several different types of membrane-enclosed specialized structures in the cell that perform specific functions for the cell
peroxisome	membrane-bound organelle that contains enzymes primarily responsible for detoxifying harmful substances
reactive oxygen species (ROS)	a group of extremely reactive peroxides and oxygen-containing radicals that may contribute to cellular damage
ribosome	cellular organelle that functions in protein synthesis
chromatin	substance consisting of DNA and associated proteins
chromosome	condensed version of chromatin
histone	family of proteins that associate with DNA in the nucleus to form chromatin
nuclear envelope	membrane that surrounds the nucleus; consisting of a double lipid-bilayer
nuclear pore	one of the small, protein-lined openings found scattered throughout the nuclear envelope
nucleolus	small region of the nucleus that functions in ribosome synthesis
nucleosome	unit of chromatin consisting of a DNA strand wrapped around histone proteins
connective tissue	type of tissue that serves to hold in place, connect, and integrate the body’s organs and systems
connective tissue membrane	connective tissue that encapsulates organs and lines movable joints
cutaneous membrane	skin; epithelial tissue made up of a stratified squamous epithelial cells that cover the outside of the body
ectoderm	outermost embryonic germ layer from which the epidermis and the nervous tissue derive
endoderm	innermost embryonic germ layer from which most of the digestive system and lower respiratory system derive
epithelial membrane	epithelium attached to a layer of connective tissue
epithelial tissue	type of tissue that serves primarily as a covering or lining of body parts, protecting the body; it also functions in absorption, transport, and secretion
histology	microscopic study of tissue architecture, organization, and function
lamina propria	areolar connective tissue underlying a mucous membrane
mesoderm	middle embryonic germ layer from which connective tissue, muscle tissue, and some epithelial tissue derive
mucous membrane	tissue membrane that is covered by protective mucous and lines tissue exposed to the outside environment
muscle tissue	type of tissue that is capable of contracting and generating tension in response to stimulation; produces movement.
nervous tissue	type of tissue that is capable of sending and receiving impulses through electrochemical signals.
serous membrane	type of tissue membrane that lines body cavities and lubricates them with serous fluid
synovial membrane	connective tissue membrane that lines the cavities of freely movable joints, producing synovial fluid for lubrication
tissue	group of cells that are similar in form and perform related functions
tissue membrane	thin layer or sheet of cells that covers the outside of the body, organs, and internal cavities
totipotent	embryonic cells that have the ability to differentiate into any type of cell and organ in the body
anchoring junction	mechanically attaches adjacent cells to each other or to the basement membrane
apical	that part of a cell or tissue which, in general, faces an open space
apocrine secretion	release of a substance along with the apical portion of the cell
basal lamina	thin extracellular layer that lies underneath epithelial cells and separates them from other tissues
basement membrane	in epithelial tissue, a thin layer of fibrous material that anchors the epithelial tissue to the underlying connective tissue; made up of the basal lamina and reticular lamina
cell junction	point of cell-to-cell contact that connects one cell to another in a tissue
endocrine gland	groups of cells that release chemical signals into the intercellular fluid to be picked up and transported to their target organs by blood
endothelium	tissue that lines vessels of the lymphatic and cardiovascular system, made up of a simple squamous epithelium
exocrine gland	group of epithelial cells that secrete substances through ducts that open to the skin or to internal body surfaces that lead to the exterior of the body
gap junction	allows cytoplasmic communications to occur between cells
goblet cell	unicellular gland found in columnar epithelium that secretes mucous
holocrine secretion	release of a substance caused by the rupture of a gland cell, which becomes part of the secretion
merocrine secretion	release of a substance from a gland via exocytosis
mesothelium	simple squamous epithelial tissue which covers the major body cavities and is the epithelial portion of serous membranes
mucous gland	group of cells that secrete mucous, a thick, slippery substance that keeps tissues moist and acts as a lubricant
pseudostratified columnar epithelium	tissue that consists of a single layer of irregularly shaped and sized cells that give the appearance of multiple layers; found in ducts of certain glands and the upper respiratory tract
reticular lamina	matrix containing collagen and elastin secreted by connective tissue; a component of the basement membrane
serous gland	group of cells within the serous membrane that secrete a lubricating substance onto the surface
simple columnar epithelium	tissue that consists of a single layer of column-like cells; promotes secretion and absorption in tissues and organs
simple cuboidal epithelium	tissue that consists of a single layer of cube-shaped cells; promotes secretion and absorption in ducts and tubules
simple squamous epithelium	tissue that consists of a single layer of flat scale-like cells; promotes diffusion and filtration across surface
stratified columnar epithelium	tissue that consists of two or more layers of column-like cells, contains glands and is found in some ducts
stratified cuboidal epithelium	tissue that consists of two or more layers of cube-shaped cells, found in some ducts
stratified squamous epithelium	tissue that consists of multiple layers of cells with the most apical being flat scale-like cells; protects surfaces from abrasion
tight junction	forms an impermeable barrier between cells
transitional epithelium	form of stratified epithelium found in the urinary tract, characterized by an apical layer of cells that change shape in response to the presence of urine
adipocytes	lipid storage cells
adipose tissue	specialized areolar tissue rich in stored fat
areolar tissue	(also, loose connective tissue) a type of connective tissue proper that shows little specialization with cells dispersed in the matrix
chondrocytes	cells of the cartilage
collagen fiber	flexible fibrous proteins that give connective tissue tensile strength
connective tissue proper	connective tissue containing a viscous matrix, fibers, and cells.
deep fascia	layer of dense connective tissue surrounding muscles, bones, and nerves
dense connective tissue	connective tissue proper that contains many fibers that provide both elasticity and protection
elastic cartilage	type of cartilage, with elastin as the major protein, characterized by rigid support as well as elasticity
elastic fiber	fibrous protein within connective tissue that contains a high percentage of the protein elastin that allows the fibers to stretch and return to original size
fibroblast	most abundant cell type in connective tissue, secretes protein fibers and matrix into the extracellular space
fibrocartilage	tough form of cartilage, made of thick bundles of collagen fibers embedded in chondroitin sulfate ground substance
fibrocyte	less active form of fibroblast
fluid connective tissue	specialized cells that circulate in a watery fluid containing salts, nutrients, and dissolved proteins
ground substance	fluid or semi-fluid portion of the matrix
hyaline cartilage	most common type of cartilage, smooth and made of short collagen fibers embedded in a chondroitin sulfate ground substance
lacunae	(singular = lacuna) small spaces in bone or cartilage tissue that cells occupy
loose connective tissue	(also, areolar tissue) type of connective tissue proper that shows little specialization with cells dispersed in the matrix
matrix	extracellular material which is produced by the cells embedded in it, containing ground substance and fibers
mesenchymal cell	adult stem cell from which most connective tissue cells are derived
mesenchyme	embryonic tissue from which connective tissue cells derive
mucous connective tissue	specialized loose connective tissue present in the umbilical cord
parenchyma	functional cells of a gland or organ, in contrast with the supportive or connective tissue of a gland or organ
reticular fiber	fine fibrous protein, made of collagen subunits, which cross-link to form supporting “nets” within connective tissue
reticular tissue	type of loose connective tissue that provides a supportive framework to soft organs, such as lymphatic tissue, spleen, and the liver
supportive connective tissue	type of connective tissue that provides strength to the body and protects soft tissue
subserous fascia	layer of connective tissues between the deep fascia and serous membranes superficial fascia
superficial fascia	layer of connective tissues found deep to the cutaneous membrane
cardiac muscle	heart muscle, under involuntary control, composed of striated cells that attach to form fibers, each cell contains a single nucleus, contracts autonomously
myocyte	muscle cells
skeletal muscle	usually attached to bone, under voluntary control, each cell is a fiber that is multinucleated and striated
smooth muscle	under involuntary control, moves internal organs, cells contain a single nucleus, are spindle-shaped, and do not appear striated; each cell is a fiber
striation	alignment of parallel actin and myosin filaments which form a banded pattern
astrocyte	star-shaped cell in the central nervous system that regulates ions and uptake and/or breakdown of some neurotransmitters and contributes to the formation of the blood-brain barrier
myelin	layer of lipid inside some neuroglial cells that wraps around the axons of some neurons
neuroglia	supportive neural cells
neuron	excitable neural cell that transfer nerve impulses
oligodendrocyte	neuroglial cell that produces myelin in the brain
Schwann cell	neuroglial cell that produces myelin in the peripheral nervous system
apoptosis	programmed cell death
atrophy	loss of mass and function
clotting	also called coagulation; complex process by which blood components form a plug to stop bleeding
histamine	chemical compound released by mast cells in response to injury that causes vasodilation and endothelium permeability
inflammation	response of tissue to injury
necrosis	accidental death of cells and tissues
primary union	edges of a wound are close enough together to promote healing without the use of stitches to hold them close
secondary union	wound healing facilitated by wound contraction
vasodilation	widening of blood vessels
wound contraction	process whereby the borders of a wound are physically drawn together
Meissner corpuscle	(also, tactile corpuscle) receptor in the skin that responds to light touch
Pacinian corpuscle	(also, lamellated corpuscle) receptor in the skin that responds to vibration
rickets	disease in children caused by vitamin D deficiency, which leads to the weakening of bones
vitamin D	compound that aids absorption of calcium and phosphates in the intestine to improve bone health
albinism	genetic disorder that affects the skin, in which there is no melanin production
basal cell	type of stem cell found in the stratum basale and in the hair matrix that continually undergoes cell division, producing the keratinocytes of the epidermis
dermal papilla	(plural = dermal papillae) extension of the papillary layer of the dermis that increases surface contact between the epidermis and dermis
dermis	layer of skin between the epidermis and hypodermis, composed mainly of connective tissue and containing blood vessels, hair follicles, sweat glands, and other structures
desmosome	structure that forms an impermeable junction between cells
elastin fibers	fibers made of the protein elastin that increase the elasticity of the dermis
eleiden	clear protein-bound lipid found in the stratum lucidum that is derived from keratohyalin and helps to prevent water loss
epidermis	outermost tissue layer of the skin
hypodermis	connective tissue connecting the integument to the underlying bone and muscle
integumentary system	skin and its accessory structures
keratin	type of structural protein that gives skin, hair, and nails its hard, water-resistant properties
keratinocyte	cell that produces keratin and is the most predominant type of cell found in the epidermis
keratohyalin	granulated protein found in the stratum granulosum
Langerhans cell	specialized dendritic cell found in the stratum spinosum that functions as a macrophage
melanin	pigment that determines the color of hair and skin
melanocyte	cell found in the stratum basale of the epidermis that produces the pigment melanin
melanosome	intercellular vesicle that transfers melanin from melanocytes into keratinocytes of the epidermis
Merkel cell	receptor cell in the stratum basale of the epidermis that responds to the sense of touch
papillary layer	superficial layer of the dermis, made of loose, areolar connective tissue
reticular layer	deeper layer of the dermis; it has a reticulated appearance due to the presence of abundant collagen and elastin fibers
stratum basale	deepest layer of the epidermis, made of epidermal stem cells
stratum corneum	most superficial layer of the epidermis
stratum granulosum	layer of the epidermis superficial to the stratum spinosum
stratum lucidum	layer of the epidermis between the stratum granulosum and stratum corneum, found only in thick skin covering the palms, soles of the feet, and digits
stratum spinosum	layer of the epidermis superficial to the stratum basale, characterized by the presence of desmosomes
vitiligo	skin condition in which melanocytes in certain areas lose the ability to produce melanin, possibly due an autoimmune reaction that leads to loss of color in patches
anagen	active phase of the hair growth cycle
apocrine sweat gland	type of sweat gland that is associated with hair follicles in the armpits and genital regions
arrector pili	smooth muscle that is activated in response to external stimuli that pull on hair follicles and make the hair “stand up”
catagen	transitional phase marking the end of the anagen phase of the hair growth cycle
cortex	in hair, the second or middle layer of keratinocytes originating from the hair matrix, as seen in a cross-section of the hair bulb
cuticle	in hair, the outermost layer of keratinocytes originating from the hair matrix, as seen in a cross-section of the hair bulb
eccrine sweat gland	type of sweat gland that is common throughout the skin surface; it produces a hypotonic sweat for thermoregulation
eponychium	nail fold that meets the proximal end of the nail body, also called the cuticle
external root sheath	outer layer of the hair follicle that is an extension of the epidermis, which encloses the hair root
glassy membrane	layer of connective tissue that surrounds the base of the hair follicle, connecting it to the dermis
hair	keratinous filament growing out of the epidermis
hair bulb	structure at the base of the hair root that surrounds the dermal papilla
hair follicle	cavity or sac from which hair originates
hair matrix	layer of basal cells from which a strand of hair grows
hair papilla	mass of connective tissue, blood capillaries, and nerve endings at the base of the hair follicle
hair root	part of hair that is below the epidermis anchored to the follicle
hair shaft	part of hair that is above the epidermis but is not anchored to the follicle
hyponychium	thickened layer of stratum corneum that lies below the free edge of the nail
internal root sheath	innermost layer of keratinocytes in the hair follicle that surround the hair root up to the hair shaft
lunula	basal part of the nail body that consists of a crescent-shaped layer of thick epithelium
medulla	in hair, the innermost layer of keratinocytes originating from the hair matrix
nail bed	layer of epidermis upon which the nail body forms
nail body	main keratinous plate that forms the nail
nail cuticle	fold of epithelium that extends over the nail bed, also called the eponychium
nail fold	fold of epithelium at that extend over the sides of the nail body, holding it in place
nail root	part of the nail that is lodged deep in the epidermis from which the nail grows
sebaceous gland	type of oil gland found in the dermis all over the body and helps to lubricate and waterproof the skin and hair by secreting sebum
sebum	oily substance that is composed of a mixture of lipids that lubricates the skin and hair
sudoriferous gland	sweat gland
telogen	resting phase of the hair growth cycle initiated with catagen and terminated by the beginning of a new anagen phase of hair growth
acne	skin condition due to infected sebaceous glands
basal cell carcinoma	cancer that originates from basal cells in the epidermis of the skin
bedsore	sore on the skin that develops when regions of the body start necrotizing due to constant pressure and lack of blood supply; also called decubitis ulcers
callus	thickened area of skin that arises due to constant abrasion
corn	type of callus that is named for its shape and the elliptical motion of the abrasive force
eczema	skin condition due to an allergic reaction, which resembles a rash
first-degree burn	superficial burn that injures only the epidermis
fourth-degree burn	burn in which full thickness of the skin and underlying muscle and bone is damaged
keloid	type of scar that has layers raised above the skin surface
melanoma	type of skin cancer that originates from the melanocytes of the skin
metastasis	spread of cancer cells from a source to other parts of the body
scar	collagen-rich skin formed after the process of wound healing that is different from normal skin
second-degree burn	partial-thickness burn that injures the epidermis and a portion of the dermis
squamous cell carcinoma	type of skin cancer that originates from the stratum spinosum of the epidermis
stretch mark	mark formed on the skin due to a sudden growth spurt and expansion of the dermis beyond its elastic limits
third-degree burn	burn that penetrates and destroys the full thickness of the skin (epidermis and dermis)
bone	hard, dense connective tissue that forms the structural elements of the skeleton
cartilage	semi-rigid connective tissue found on the skeleton in areas where flexibility and smooth surfaces support movement
hematopoiesis	production of blood cells, which occurs in the red marrow of the bones
orthopedist	doctor who specializes in diagnosing and treating musculoskeletal disorders and injuries
osseous tissue	bone tissue; a hard, dense connective tissue that forms the structural elements of the skeleton
red marrow	connective tissue in the interior cavity of a bone where hematopoiesis takes place
skeletal system	organ system composed of bones and cartilage that provides for movement, support, and protection
yellow marrow	connective tissue in the interior cavity of a bone where fat is stored
flat bone	thin and curved bone; serves as a point of attachment for muscles and protects internal organs
irregular bone	bone of complex shape; protects internal organs from compressive forces
long bone	cylinder-shaped bone that is longer than it is wide; functions as a lever
sesamoid bone	small, round bone embedded in a tendon; protects the tendon from compressive forces
short bone	cube-shaped bone that is approximately equal in length, width, and thickness; provides limited motion
articular cartilage	thin layer of cartilage covering an epiphysis; reduces friction and acts as a shock absorber
articulation	where two bone surfaces meet
canaliculi	(singular = canaliculus) channels within the bone matrix that house one of an osteocyte’s many cytoplasmic extensions that it uses to communicate and receive nutrients
central canal	longitudinal channel in the center of each osteon; contains blood vessels, nerves, and lymphatic vessels; also known as the Haversian canal
compact bone	dense osseous tissue that can withstand compressive forces
diaphysis	tubular shaft that runs between the proximal and distal ends of a long bone
diploë	layer of spongy bone, that is sandwiched between two the layers of compact bone found in flat bones
endosteum	delicate membranous lining of a bone’s medullary cavity
epiphyseal plate	(also, growth plate) sheet of hyaline cartilage in the metaphysis of an immature bone; replaced by bone tissue as the organ grows in length
epiphysis	wide section at each end of a long bone; filled with spongy bone and red marrow
hole	opening or depression in a bone
lacunae	(singular = lacuna) spaces in a bone that house an osteocyte
medullary cavity	hollow region of the diaphysis; filled with yellow marrow
nutrient foramen	small opening in the middle of the external surface of the diaphysis, through which an artery enters the bone to provide nourishment
osteoblast	cell responsible for forming new bone
osteoclast	cell responsible for resorbing bone
osteocyte	primary cell in mature bone; responsible for maintaining the matrix
osteogenic cell	undifferentiated cell with high mitotic activity; the only bone cells that divide; they differentiate and develop into osteoblasts
osteon	(also, Haversian system) basic structural unit of compact bone; made of concentric layers of calcified matrix
perforating canal	(also, Volkmann’s canal) channel that branches off from the central canal and houses vessels and nerves that extend to the periosteum and endosteum
periosteum	fibrous membrane covering the outer surface of bone and continuous with ligaments
projection	bone markings where part of the surface sticks out above the rest of the surface, where tendons and ligaments attach
spongy bone	(also, cancellous bone) trabeculated osseous tissue that supports shifts in weight distribution
trabeculae	(singular = trabecula) spikes or sections of the lattice-like matrix in spongy bone
endochondral ossification	process in which bone forms by replacing hyaline cartilage
epiphyseal line	completely ossified remnant of the epiphyseal plate
intramembranous ossification	process by which bone forms directly from mesenchymal tissue
modeling	process, during bone growth, by which bone is resorbed on one surface of a bone and deposited on another
ossification	(also, osteogenesis) bone formation
ossification center	cluster of osteoblasts found in the early stages of intramembranous ossification
osteoid	uncalcified bone matrix secreted by osteoblasts
perichondrium	membrane that covers cartilage
primary ossification center	region, deep in the periosteal collar, where bone development starts during endochondral ossification
proliferative zone	region of the epiphyseal plate that makes new chondrocytes to replace those that die at the diaphyseal end of the plate and contributes to longitudinal growth of the epiphyseal plate
remodeling	process by which osteoclasts resorb old or damaged bone at the same time as and on the same surface where osteoblasts form new bone to replace that which is resorbed
reserve zone	region of the epiphyseal plate that anchors the plate to the osseous tissue of the epiphysis
secondary ossification center	region of bone development in the epiphyses
zone of calcified matrix	region of the epiphyseal plate closest to the diaphyseal end; functions to connect the epiphyseal plate to the diaphysis
zone of maturation and hypertrophy	region of the epiphyseal plate where chondrocytes from the proliferative zone grow and mature and contribute to the longitudinal growth of the epiphyseal plate
closed reduction	manual manipulation of a broken bone to set it into its natural position without surgery
external callus	collar of hyaline cartilage and bone that forms around the outside of a fracture
fracture	broken bone
fracture hematoma	blood clot that forms at the site of a broken bone
internal callus	fibrocartilaginous matrix, in the endosteal region, between the two ends of a broken bone
open reduction	surgical exposure of a bone to reset a fracture
osteoporosis	disease characterized by a decrease in bone mass; occurs when the rate of bone resorption exceeds the rate of bone formation, a common occurrence as the body ages
appendicular skeleton	all bones of the upper and lower limbs, plus the girdle bones that attach each limb to the axial skeleton
axial skeleton	central, vertical axis of the body, including the skull, vertebral column, and thoracic cage
coccyx	small bone located at inferior end of the adult vertebral column that is formed by the fusion of four coccygeal vertebrae; also referred to as the “tailbone”
ear ossicles	three small bones located in the middle ear cavity that serve to transmit sound vibrations to the inner ear
hyoid bone	small, U-shaped bone located in upper neck that does not contact any other bone
ribs	thin, curved bones of the chest wall
sacrum	single bone located near the inferior end of the adult vertebral column that is formed by the fusion of five sacral vertebrae; forms the posterior portion of the pelvis
skeleton	bones of the body
skull	bony structure that forms the head, face, and jaws, and protects the brain; consists of 22 bones
sternum	flattened bone located at the center of the anterior chest
thoracic cage	consists of 12 pairs of ribs and sternum
vertebra	individual bone in the neck and back regions of the vertebral column
vertebral column	entire sequence of bones that extend from the skull to the tailbone
alveolar process of the mandible	upper border of mandibular body that contains the lower teeth
alveolar process of the maxilla	curved, inferior margin of the maxilla that supports and anchors the upper teeth
angle of the mandible	rounded corner located at outside margin of the body and ramus junction
anterior cranial fossa	shallowest and most anterior cranial fossa of the cranial base that extends from the frontal bone to the lesser wing of the sphenoid bone
articular tubercle	smooth ridge located on the inferior skull, immediately anterior to the mandibular fossa
brain case	portion of the skull that contains and protects the brain, consisting of the eight bones that form the cranial base and rounded upper skull
calvaria	(also, skullcap) rounded top of the skull
carotid canal	zig-zag tunnel providing passage through the base of the skull for the internal carotid artery to the brain; begins anteromedial to the styloid process and terminates in the middle cranial cavity, near the posterior-lateral base of the sella turcica
condylar process of the mandible	thickened upward projection from posterior margin of mandibular ramus
condyle	oval-shaped process located at the top of the condylar process of the mandible
coronal suture	joint that unites the frontal bone to the right and left parietal bones across the top of the skull
coronoid process of the mandible	flattened upward projection from the anterior margin of the mandibular ramus
cranial cavity	interior space of the skull that houses the brain
cranium	skull
cribriform plate	small, flattened areas with numerous small openings, located to either side of the midline in the floor of the anterior cranial fossa; formed by the ethmoid bone
crista galli	small upward projection located at the midline in the floor of the anterior cranial fossa; formed by the ethmoid bone
ethmoid air cell	one of several small, air-filled spaces located within the lateral sides of the ethmoid bone, between the orbit and upper nasal cavity
ethmoid bone	unpaired bone that forms the roof and upper, lateral walls of the nasal cavity, portions of the floor of the anterior cranial fossa and medial wall of orbit, and the upper portion of the nasal septum
external acoustic meatus	ear canal opening located on the lateral side of the skull
external occipital protuberance	small bump located at the midline on the posterior skull
facial bones	fourteen bones that support the facial structures and form the upper and lower jaws and the hard palate
foramen lacerum	irregular opening in the base of the skull, located inferior to the exit of carotid canal
foramen magnum	large opening in the occipital bone of the skull through which the spinal cord emerges and the vertebral arteries enter the cranium
foramen ovale of the middle cranial fossa	oval-shaped opening in the floor of the middle cranial fossa
foramen rotundum	round opening in the floor of the middle cranial fossa, located between the superior orbital fissure and foramen ovale
foramen spinosum	small opening in the floor of the middle cranial fossa, located lateral to the foramen ovale
frontal bone	unpaired bone that forms forehead, roof of orbit, and floor of anterior cranial fossa
frontal sinus	air-filled space within the frontal bone; most anterior of the paranasal sinuses
glabella	slight depression of frontal bone, located at the midline between the eyebrows
greater wings of sphenoid bone	lateral projections of the sphenoid bone that form the anterior wall of the middle cranial fossa and an area of the lateral skull
hard palate	bony structure that forms the roof of the mouth and floor of the nasal cavity, formed by the palatine process of the maxillary bones and the horizontal plate of the palatine bones
horizontal plate	medial extension from the palatine bone that forms the posterior quarter of the hard palate
hypoglossal canal	paired openings that pass anteriorly from the anterior-lateral margins of the foramen magnum deep to the occipital condyles
hypophyseal (pituitary) fossa	shallow depression on top of the sella turcica that houses the pituitary (hypophyseal) gland
inferior nasal concha	one of the paired bones that project from the lateral walls of the nasal cavity to form the largest and most inferior of the nasal conchae
infraorbital foramen	opening located on anterior skull, below the orbit
infratemporal fossa	space on lateral side of skull, below the level of the zygomatic arch and deep (medial) to the ramus of the mandible
internal acoustic meatus	opening into petrous ridge, located on the lateral wall of the posterior cranial fossa
jugular foramen	irregularly shaped opening located in the lateral floor of the posterior cranial cavity
lacrimal bone	paired bones that contribute to the anterior-medial wall of each orbit
lacrimal fossa	shallow depression in the anterior-medial wall of the orbit, formed by the lacrimal bone that gives rise to the nasolacrimal canal
lambdoid suture	inverted V-shaped joint that unites the occipital bone to the right and left parietal bones on the posterior skull
lateral pterygoid plate	paired, flattened bony projections of the sphenoid bone located on the inferior skull, lateral to the medial pterygoid plate
lesser wings of the sphenoid bone	lateral extensions of the sphenoid bone that form the bony lip separating the anterior and middle cranial fossae
lingula	small flap of bone located on the inner (medial) surface of mandibular ramus, next to the mandibular foramen
mandible	unpaired bone that forms the lower jaw bone; the only moveable bone of the skull
mandibular foramen	opening located on the inner (medial) surface of the mandibular ramus
mandibular fossa	oval depression located on the inferior surface of the skull
mandibular notch	large U-shaped notch located between the condylar process and coronoid process of the mandible
mastoid process	large bony prominence on the inferior, lateral skull, just behind the earlobe
maxillary bone	(also, maxilla) paired bones that form the upper jaw and anterior portion of the hard palate
maxillary sinus	air-filled space located with each maxillary bone; largest of the paranasal sinuses
medial pterygoid plate	paired, flattened bony projections of the sphenoid bone located on the inferior skull medial to the lateral pterygoid plate; form the posterior portion of the nasal cavity lateral wall
mental foramen	opening located on the anterior-lateral side of the mandibular body
mental protuberance	inferior margin of anterior mandible that forms the chin
middle cranial fossa	centrally located cranial fossa that extends from the lesser wings of the sphenoid bone to the petrous ridge
middle nasal concha	nasal concha formed by the ethmoid bone that is located between the superior and inferior conchae
mylohyoid line	bony ridge located along the inner (medial) surface of the mandibular body
nasal bone	paired bones that form the base of the nose
nasal cavity	opening through skull for passage of air
nasal conchae	curved bony plates that project from the lateral walls of the nasal cavity; include the superior and middle nasal conchae, which are parts of the ethmoid bone, and the independent inferior nasal conchae bone
nasal septum	flat, midline structure that divides the nasal cavity into halves, formed by the perpendicular plate of the ethmoid bone, vomer bone, and septal cartilage
nasolacrimal canal	passage for drainage of tears that extends downward from the medial-anterior orbit to the nasal cavity, terminating behind the inferior nasal conchae
occipital bone	unpaired bone that forms the posterior portions of the brain case and base of the skull
occipital condyle	paired, oval-shaped bony knobs located on the inferior skull, to either side of the foramen magnum
optic canal	opening spanning between middle cranial fossa and posterior orbit
orbit	bony socket that contains the eyeball and associated muscles
palatine bone	paired bones that form the posterior quarter of the hard palate and a small area in floor of the orbit
palatine process	medial projection from the maxilla bone that forms the anterior three quarters of the hard palate
paranasal sinuses	cavities within the skull that are connected to the conchae that serve to warm and humidify incoming air, produce mucus, and lighten the weight of the skull; consist of frontal, maxillary, sphenoidal, and ethmoidal sinuses
parietal bone	paired bones that form the upper, lateral sides of the skull
perpendicular plate of the ethmoid bone	downward, midline extension of the ethmoid bone that forms the superior portion of the nasal septum
petrous ridge	petrous portion of the temporal bone that forms a large, triangular ridge in the floor of the cranial cavity, separating the middle and posterior cranial fossae; houses the middle and inner ear structures
posterior cranial fossa	deepest and most posterior cranial fossa; extends from the petrous ridge to the occipital bone
pterion	H-shaped suture junction region that unites the frontal, parietal, temporal, and sphenoid bones on the lateral side of the skull
ramus of the mandible	vertical portion of the mandible
sagittal suture	joint that unites the right and left parietal bones at the midline along the top of the skull
sella turcica	elevated area of sphenoid bone located at midline of the middle cranial fossa
septal cartilage	flat cartilage structure that forms the anterior portion of the nasal septum
sphenoid bone	unpaired bone that forms the central base of skull
sphenoid sinus	air-filled space located within the sphenoid bone; most posterior of the paranasal sinuses
squamous suture	joint that unites the parietal bone to the squamous portion of the temporal bone on the lateral side of the skull
styloid process	downward projecting, elongated bony process located on the inferior aspect of the skull
stylomastoid foramen	opening located on inferior skull, between the styloid process and mastoid process
superior nasal concha	smallest and most superiorly located of the nasal conchae; formed by the ethmoid bone
superior nuchal line	paired bony lines on the posterior skull that extend laterally from the external occipital protuberance
superior orbital fissure	irregularly shaped opening between the middle cranial fossa and the posterior orbit
supraorbital foramen	opening located on anterior skull, at the superior margin of the orbit
supraorbital margin	superior margin of the orbit
suture	junction line at which adjacent bones of the skull are united by fibrous connective tissue
temporal bone	paired bones that form the lateral, inferior portions of the skull, with squamous, mastoid, and petrous portions
temporal fossa	shallow space on the lateral side of the skull, above the level of the zygomatic arch
temporal process of the zygomatic bone	short extension from the zygomatic bone that forms the anterior portion of the zygomatic arch
vomer bone	unpaired bone that forms the inferior and posterior portions of the nasal septum
zygomatic arch	elongated, free-standing arch on the lateral skull, formed anteriorly by the temporal process of the zygomatic bone and posteriorly by the zygomatic process of the temporal bone
zygomatic bone	cheekbone; paired bones that contribute to the lateral orbit and anterior zygomatic arch
zygomatic process of the temporal bone	extension from the temporal bone that forms the posterior portion of the zygomatic arch
anterior arch	anterior portion of the ring-like C1 (atlas) vertebra
anterior longitudinal ligament	ligament that runs the length of the vertebral column, uniting the anterior aspects of the vertebral bodies
anterior (ventral) sacral foramen	one of the series of paired openings located on the anterior (ventral) side of the sacrum
anulus fibrosus	tough, fibrous outer portion of an intervertebral disc, which is strongly anchored to the bodies of the adjacent vertebrae
atlas	first cervical (C1) vertebra
axis	second cervical (C2) vertebra
cervical curve	posteriorly concave curvature of the cervical vertebral column region; a secondary curve of the vertebral column
cervical vertebrae	seven vertebrae numbered as C1–C7 that are located in the neck region of the vertebral column
costal facet	site on the lateral sides of a thoracic vertebra for articulation with the head of a rib
dens	bony projection (odontoid process) that extends upward from the body of the C2 (axis) vertebra
facet	small, flattened area on a bone for an articulation (joint) with another bone, or for muscle attachment
inferior articular process	bony process that extends downward from the vertebral arch of a vertebra that articulates with the superior articular process of the next lower vertebra
intervertebral disc	structure located between the bodies of adjacent vertebrae that strongly joins the vertebrae; provides padding, weight bearing ability, and enables vertebral column movements
intervertebral foramen	opening located between adjacent vertebrae for exit of a spinal nerve
kyphosis	(also, humpback or hunchback) excessive posterior curvature of the thoracic vertebral column region
lamina	portion of the vertebral arch on each vertebra that extends between the transverse and spinous process
lateral sacral crest	paired irregular ridges running down the lateral sides of the posterior sacrum that was formed by the fusion of the transverse processes from the five sacral vertebrae
ligamentum flavum	series of short ligaments that unite the lamina of adjacent vertebrae
lordosis	(also, swayback) excessive anterior curvature of the lumbar vertebral column region
lumbar curve	posteriorly concave curvature of the lumbar vertebral column region; a secondary curve of the vertebral column
lumbar vertebrae	five vertebrae numbered as L1–L5 that are located in lumbar region (lower back) of the vertebral column
median sacral crest	irregular ridge running down the midline of the posterior sacrum that was formed from the fusion of the spinous processes of the five sacral vertebrae
nuchal ligament	expanded portion of the supraspinous ligament within the posterior neck; interconnects the spinous processes of the cervical vertebrae and attaches to the base of the skull
nucleus pulposus	gel-like central region of an intervertebral disc; provides for padding, weight-bearing, and movement between adjacent vertebrae
pedicle	portion of the vertebral arch that extends from the vertebral body to the transverse process
posterior arch	posterior portion of the ring-like C1 (atlas) vertebra
posterior longitudinal ligament	ligament that runs the length of the vertebral column, uniting the posterior sides of the vertebral bodies
posterior (dorsal) sacral foramen	one of the series of paired openings located on the posterior (dorsal) side of the sacrum
primary curve	anteriorly concave curvatures of the thoracic and sacrococcygeal regions that are retained from the original fetal curvature of the vertebral column
sacral canal	bony tunnel that runs through the sacrum
sacral foramina	series of paired openings for nerve exit located on both the anterior (ventral) and posterior (dorsal) aspects of the sacrum
sacral hiatus	inferior opening and termination of the sacral canal
sacral promontory	anterior lip of the base (superior end) of the sacrum
sacrococcygeal curve	anteriorly concave curvature formed by the sacrum and coccyx; a primary curve of the vertebral column
scoliosis	abnormal lateral curvature of the vertebral column
secondary curve	posteriorly concave curvatures of the cervical and lumbar regions of the vertebral column that develop after the time of birth
spinous process	unpaired bony process that extends posteriorly from the vertebral arch of a vertebra
superior articular process	bony process that extends upward from the vertebral arch of a vertebra that articulates with the inferior articular process of the next higher vertebra
superior articular process of the sacrum	paired processes that extend upward from the sacrum to articulate (join) with the inferior articular processes from the L5 vertebra
supraspinous ligament	ligament that interconnects the spinous processes of the thoracic and lumbar vertebrae
thoracic curve	anteriorly concave curvature of the thoracic vertebral column region; a primary curve of the vertebral column
thoracic vertebrae	twelve vertebrae numbered as T1–T12 that are located in the thoracic region (upper back) of the vertebral column
transverse foramen	opening found only in the transverse processes of cervical vertebrae
transverse process	paired bony processes that extends laterally from the vertebral arch of a vertebra
vertebral arch	bony arch formed by the posterior portion of each vertebra that surrounds and protects the spinal cord
vertebral (spinal) canal	bony passageway within the vertebral column for the spinal cord that is formed by the series of individual vertebral foramina
vertebral foramen	opening associated with each vertebra defined by the vertebral arch that provides passage for the spinal cord
angle of the rib	portion of rib with greatest curvature; together, the rib angles form the most posterior extent of the thoracic cage
body of the rib	shaft portion of a rib
clavicular notch	paired notches located on the superior-lateral sides of the sternal manubrium, for articulation with the clavicle
costal cartilage	hyaline cartilage structure attached to the anterior end of each rib that provides for either direct or indirect attachment of most ribs to the sternum
costal groove	shallow groove along the inferior margin of a rib that provides passage for blood vessels and a nerve
false ribs	vertebrochondral ribs 8–12 whose costal cartilage either attaches indirectly to the sternum via the costal cartilage of the next higher rib or does not attach to the sternum at all
floating ribs	vertebral ribs 11–12 that do not attach to the sternum or to the costal cartilage of another rib
head of the rib	posterior end of a rib that articulates with the bodies of thoracic vertebrae
jugular (suprasternal) notch	shallow notch located on superior surface of sternal manubrium
manubrium	expanded, superior portion of the sternum
neck of the rib	narrowed region of a rib, next to the rib head
sternal angle	junction line between manubrium and body of the sternum and the site for attachment of the second rib to the sternum
true ribs	vertebrosternal ribs 1–7 that attach via their costal cartilage directly to the sternum
tubercle of the rib	small bump on the posterior side of a rib for articulation with the transverse process of a thoracic vertebra
fontanelle	expanded area of fibrous connective tissue that separates the brain case bones of the skull prior to birth and during the first year after birth
notochord	rod-like structure along dorsal side of the early embryo; largely disappears during later development but does contribute to formation of the intervertebral discs
sclerotome	medial portion of a somite consisting of mesenchyme tissue that will give rise to bone, cartilage, and fibrous connective tissues
somite	one of the paired, repeating blocks of tissue located on either side of the notochord in the early embryo
acromial end of the clavicle	lateral end of the clavicle that articulates with the acromion of the scapula
acromial process	acromion of the scapula
acromioclavicular joint	articulation between the acromion of the scapula and the acromial end of the clavicle
acromion	flattened bony process that extends laterally from the scapular spine to form the bony tip of the shoulder
clavicle	collarbone; elongated bone that articulates with the manubrium of the sternum medially and the acromion of the scapula laterally
coracoclavicular ligament	strong band of connective tissue that anchors the coracoid process of the scapula to the lateral clavicle; provides important indirect support for the acromioclavicular joint
coracoid process	short, hook-like process that projects anteriorly and laterally from the superior margin of the scapula
costoclavicular ligament	band of connective tissue that unites the medial clavicle with the first rib
fossa	(plural = fossae) shallow depression on the surface of a bone
glenohumeral joint	shoulder joint; formed by the articulation between the glenoid cavity of the scapula and the head of the humerus
glenoid cavity	(also, glenoid fossa) shallow depression located on the lateral scapula, between the superior and lateral borders
inferior angle of the scapula	inferior corner of the scapula located where the medial and lateral borders meet
infraglenoid tubercle	small bump or roughened area located on the lateral border of the scapula, near the inferior margin of the glenoid cavity
infraspinous fossa	broad depression located on the posterior scapula, inferior to the spine
lateral border of the scapula	diagonally oriented lateral margin of the scapula
medial border of the scapula	elongated, medial margin of the scapula
pectoral girdle	shoulder girdle; the set of bones, consisting of the scapula and clavicle, which attaches each upper limb to the axial skeleton
scapula	shoulder blade bone located on the posterior side of the shoulder
spine of the scapula	prominent ridge passing mediolaterally across the upper portion of the posterior scapular surface
sternal end of the clavicle	medial end of the clavicle that articulates with the manubrium of the sternum
sternoclavicular joint	articulation between the manubrium of the sternum and the sternal end of the clavicle; forms the only bony attachment between the pectoral girdle of the upper limb and the axial skeleton
subscapular fossa	broad depression located on the anterior (deep) surface of the scapula
superior angle of the scapula	corner of the scapula between the superior and medial borders of the scapula
superior border of the scapula	superior margin of the scapula
supraglenoid tubercle	small bump located at the superior margin of the glenoid cavity
suprascapular notch	small notch located along the superior border of the scapula, medial to the coracoid process
supraspinous fossa	narrow depression located on the posterior scapula, superior to the spine
anatomical neck	line on the humerus located around the outside margin of the humeral head
arm	region of the upper limb located between the shoulder and elbow joints; contains the humerus bone
bicipital groove	intertubercular groove; narrow groove located between the greater and lesser tubercles of the humerus
capitate	from the lateral side, the third of the four distal carpal bones; articulates with the scaphoid and lunate proximally, the trapezoid laterally, the hamate medially, and primarily with the third metacarpal distally
capitulum	knob-like bony structure located anteriorly on the lateral, distal end of the humerus
carpal bone	one of the eight small bones that form the wrist and base of the hand; these are grouped as a proximal row consisting of (from lateral to medial) the scaphoid, lunate, triquetrum, and pisiform bones, and a distal row containing (from lateral to medial) the trapezium, trapezoid, capitate, and hamate bones
carpal tunnel	passageway between the anterior forearm and hand formed by the carpal bones and flexor retinaculum
carpometacarpal joint	articulation between one of the carpal bones in the distal row and a metacarpal bone of the hand
coronoid fossa	depression on the anterior surface of the humerus above the trochlea; this space receives the coronoid process of the ulna when the elbow is maximally flexed
coronoid process of the ulna	projecting bony lip located on the anterior, proximal ulna; forms the inferior margin of the trochlear notch
deltoid tuberosity	roughened, V-shaped region located laterally on the mid-shaft of the humerus
distal radioulnar joint	articulation between the head of the ulna and the ulnar notch of the radius
elbow joint	joint located between the upper arm and forearm regions of the upper limb; formed by the articulations between the trochlea of the humerus and the trochlear notch of the ulna, and the capitulum of the humerus and the head of the radius
flexor retinaculum	strong band of connective tissue at the anterior wrist that spans the top of the U-shaped grouping of the carpal bones to form the roof of the carpal tunnel
forearm	region of the upper limb located between the elbow and wrist joints; contains the radius and ulna bones
greater tubercle	enlarged prominence located on the lateral side of the proximal humerus
hamate	from the lateral side, the fourth of the four distal carpal bones; articulates with the lunate and triquetrum proximally, the fourth and fifth metacarpals distally, and the capitate laterally
hand	region of the upper limb distal to the wrist joint
head of the humerus	smooth, rounded region on the medial side of the proximal humerus; articulates with the glenoid fossa of the scapula to form the glenohumeral (shoulder) joint
head of the radius	disc-shaped structure that forms the proximal end of the radius; articulates with the capitulum of the humerus as part of the elbow joint, and with the radial notch of the ulna as part of the proximal radioulnar joint
head of the ulna	small, rounded distal end of the ulna; articulates with the ulnar notch of the distal radius, forming the distal radioulnar joint
hook of the hamate bone	bony extension located on the anterior side of the hamate carpal bone
humerus	single bone of the upper arm
interosseous border of the radius	narrow ridge located on the medial side of the radial shaft; for attachment of the interosseous membrane between the ulna and radius bones
interosseous border of the ulna	narrow ridge located on the lateral side of the ulnar shaft; for attachment of the interosseous membrane between the ulna and radius
interosseous membrane of the forearm	sheet of dense connective tissue that unites the radius and ulna bones
interphalangeal joint	articulation between adjacent phalanx bones of the hand or foot digits
intertubercular groove (sulcus)	bicipital groove; narrow groove located between the greater and lesser tubercles of the humerus
lateral epicondyle of the humerus	small projection located on the lateral side of the distal humerus
lateral supracondylar ridge	narrow, bony ridge located along the lateral side of the distal humerus, superior to the lateral epicondyle
lesser tubercle	small, bony prominence located on anterior side of the proximal humerus
lunate	from the lateral side, the second of the four proximal carpal bones; articulates with the radius proximally, the capitate and hamate distally, the scaphoid laterally, and the triquetrum medially
medial epicondyle of the humerus	enlarged projection located on the medial side of the distal humerus
metacarpal bone	one of the five long bones that form the palm of the hand; numbered 1–5, starting on the lateral (thumb) side of the hand
metacarpophalangeal joint	articulation between the distal end of a metacarpal bone of the hand and a proximal phalanx bone of the thumb or a finger
midcarpal joint	articulation between the proximal and distal rows of the carpal bones; contributes to movements of the hand at the wrist
neck of the radius	narrowed region immediately distal to the head of the radius
olecranon fossa	large depression located on the posterior side of the distal humerus; this space receives the olecranon process of the ulna when the elbow is fully extended
olecranon process	expanded posterior and superior portions of the proximal ulna; forms the bony tip of the elbow
phalanx bone of the hand	(plural = phalanges) one of the 14 bones that form the thumb and fingers; these include the proximal and distal phalanges of the thumb, and the proximal, middle, and distal phalanx bones of the fingers two through five
pisiform	from the lateral side, the fourth of the four proximal carpal bones; articulates with the anterior surface of the triquetrum
pollex	(also, thumb) digit 1 of the hand
proximal radioulnar joint	articulation formed by the radial notch of the ulna and the head of the radius
radial fossa	small depression located on the anterior humerus above the capitulum; this space receives the head of the radius when the elbow is maximally flexed
radial notch of the ulna	small, smooth area on the lateral side of the proximal ulna; articulates with the head of the radius as part of the proximal radioulnar joint
radial tuberosity	oval-shaped, roughened protuberance located on the medial side of the proximal radius
radiocarpal joint	wrist joint, located between the forearm and hand regions of the upper limb; articulation formed proximally by the distal end of the radius and the fibrocartilaginous pad that unites the distal radius and ulna bone, and distally by the scaphoid, lunate, and triquetrum carpal bones
radius	bone located on the lateral side of the forearm
scaphoid	from the lateral side, the first of the four proximal carpal bones; articulates with the radius proximally, the trapezoid, trapezium, and capitate distally, and the lunate medially
shaft of the humerus	narrow, elongated, central region of the humerus
shaft of the radius	narrow, elongated, central region of the radius
shaft of the ulna	narrow, elongated, central region of the ulna
styloid process of the radius	pointed projection located on the lateral end of the distal radius
styloid process of the ulna	short, bony projection located on the medial end of the distal ulna
surgical neck	region of the humerus where the expanded, proximal end joins with the narrower shaft
trapezium	from the lateral side, the first of the four distal carpal bones; articulates with the scaphoid proximally, the first and second metacarpals distally, and the trapezoid medially
trapezoid	from the lateral side, the second of the four distal carpal bones; articulates with the scaphoid proximally, the second metacarpal distally, the trapezium laterally, and the capitate medially
triquetrum	from the lateral side, the third of the four proximal carpal bones; articulates with the lunate laterally, the hamate distally, and has a facet for the pisiform
trochlea	pulley-shaped region located medially at the distal end of the humerus; articulates at the elbow with the trochlear notch of the ulna
trochlear notch	large, C-shaped depression located on the anterior side of the proximal ulna; articulates at the elbow with the trochlea of the humerus
ulna	bone located on the medial side of the forearm
ulnar notch of the radius	shallow, smooth area located on the medial side of the distal radius; articulates with the head of the ulna at the distal radioulnar joint
ulnar tuberosity	roughened area located on the anterior, proximal ulna inferior to the coronoid process
acetabulum	large, cup-shaped cavity located on the lateral side of the hip bone; formed by the junction of the ilium, pubis, and ischium portions of the hip bone
anterior inferior iliac spine	small, bony projection located on the anterior margin of the ilium, below the anterior superior iliac spine
anterior sacroiliac ligament	strong ligament between the sacrum and the ilium portions of the hip bone that supports the anterior side of the sacroiliac joint
anterior superior iliac spine	rounded, anterior end of the iliac crest
arcuate line of the ilium	smooth ridge located at the inferior margin of the iliac fossa; forms the lateral portion of the pelvic brim
auricular surface of the ilium	roughened area located on the posterior, medial side of the ilium of the hip bone; articulates with the auricular surface of the sacrum to form the sacroiliac joint
coxal bone	hip bone
greater pelvis	(also, greater pelvic cavity or false pelvis) broad space above the pelvic brim defined laterally by the fan-like portion of the upper ilium
greater sciatic foramen	pelvic opening formed by the greater sciatic notch of the hip bone, the sacrum, and the sacrospinous ligament
greater sciatic notch	large, U-shaped indentation located on the posterior margin of the ilium, superior to the ischial spine
hip bone	coxal bone; single bone that forms the pelvic girdle; consists of three areas, the ilium, ischium, and pubis
iliac crest	curved, superior margin of the ilium
iliac fossa	shallow depression found on the anterior and medial surfaces of the upper ilium
ilium	superior portion of the hip bone
inferior pubic ramus	narrow segment of bone that passes inferiorly and laterally from the pubic body; joins with the ischial ramus to form the ischiopubic ramus
ischial ramus	bony extension projecting anteriorly and superiorly from the ischial tuberosity; joins with the inferior pubic ramus to form the ischiopubic ramus
ischial spine	pointed, bony projection from the posterior margin of the ischium that separates the greater sciatic notch and lesser sciatic notch
ischial tuberosity	large, roughened protuberance that forms the posteroinferior portion of the hip bone; weight-bearing region of the pelvis when sitting
ischiopubic ramus	narrow extension of bone that connects the ischial tuberosity to the pubic body; formed by the junction of the ischial ramus and inferior pubic ramus
ischium	posteroinferior portion of the hip bone
lesser pelvis	(also, lesser pelvic cavity or true pelvis) narrow space located within the pelvis, defined superiorly by the pelvic brim (pelvic inlet) and inferiorly by the pelvic outlet
lesser sciatic foramen	pelvic opening formed by the lesser sciatic notch of the hip bone, the sacrospinous ligament, and the sacrotuberous ligament
lesser sciatic notch	shallow indentation along the posterior margin of the ischium, inferior to the ischial spine
obturator foramen	large opening located in the anterior hip bone, between the pubis and ischium regions
pectineal line	narrow ridge located on the superior surface of the superior pubic ramus
pelvic brim	pelvic inlet; the dividing line between the greater and lesser pelvic regions; formed by the superior margin of the pubic symphysis, the pectineal lines of each pubis, the arcuate lines of each ilium, and the sacral promontory
pelvic girdle	hip girdle; consists of a single hip bone, which attaches a lower limb to the sacrum of the axial skeleton
pelvic inlet	pelvic brim
pelvic outlet	inferior opening of the lesser pelvis; formed by the inferior margin of the pubic symphysis, right and left ischiopubic rami and sacrotuberous ligaments, and the tip of the coccyx
pelvis	ring of bone consisting of the right and left hip bones, the sacrum, and the coccyx
posterior inferior iliac spine	small, bony projection located at the inferior margin of the auricular surface on the posterior ilium
posterior sacroiliac ligament	strong ligament spanning the sacrum and ilium of the hip bone that supports the posterior side of the sacroiliac joint
posterior superior iliac spine	rounded, posterior end of the iliac crest
pubic arch	bony structure formed by the pubic symphysis, and the bodies and inferior pubic rami of the right and left pubic bones
pubic body	enlarged, medial portion of the pubis region of the hip bone
pubic symphysis	joint formed by the articulation between the pubic bodies of the right and left hip bones
pubic tubercle	small bump located on the superior aspect of the pubic body
pubis	anterior portion of the hip bone
sacroiliac joint	joint formed by the articulation between the auricular surfaces of the sacrum and ilium
sacrospinous ligament	ligament that spans the sacrum to the ischial spine of the hip bone
sacrotuberous ligament	ligament that spans the sacrum to the ischial tuberosity of the hip bone
subpubic angle	inverted V-shape formed by the convergence of the right and left ischiopubic rami; this angle is greater than 80 degrees in females and less than 70 degrees in males
superior pubic ramus	narrow segment of bone that passes laterally from the pubic body to join the ilium
adductor tubercle	small, bony bump located on the superior aspect of the medial epicondyle of the femur
ankle joint	joint that separates the leg and foot portions of the lower limb; formed by the articulations between the talus bone of the foot inferiorly, and the distal end of the tibia, medial malleolus of the tibia, and lateral malleolus of the fibula superiorly
anterior border of the tibia	narrow, anterior margin of the tibia that extends inferiorly from the tibial tuberosity
base of the metatarsal bone	expanded, proximal end of each metatarsal bone
calcaneus	heel bone; posterior, inferior tarsal bone that forms the heel of the foot
cuboid	tarsal bone that articulates posteriorly with the calcaneus bone, medially with the lateral cuneiform bone, and anteriorly with the fourth and fifth metatarsal bones
distal tibiofibular joint	articulation between the distal fibula and the fibular notch of the tibia
femur	thigh bone; the single bone of the thigh
fibula	thin, non-weight-bearing bone found on the lateral side of the leg
fibular notch	wide groove on the lateral side of the distal tibia for articulation with the fibula at the distal tibiofibular joint
foot	portion of the lower limb located distal to the ankle joint
fovea capitis	minor indentation on the head of the femur that serves as the site of attachment for the ligament to the head of the femur
gluteal tuberosity	roughened area on the posterior side of the proximal femur, extending inferiorly from the base of the greater trochanter
greater trochanter	large, bony expansion of the femur that projects superiorly from the base of the femoral neck
hallux	big toe; digit 1 of the foot
head of the femur	rounded, proximal end of the femur that articulates with the acetabulum of the hip bone to form the hip joint
head of the fibula	small, knob-like, proximal end of the fibula; articulates with the inferior aspect of the lateral condyle of the tibia
head of the metatarsal bone	expanded, distal end of each metatarsal bone
hip joint	joint located at the proximal end of the lower limb; formed by the articulation between the acetabulum of the hip bone and the head of the femur
intercondylar eminence	irregular elevation on the superior end of the tibia, between the articulating surfaces of the medial and lateral condyles
intercondylar fossa	deep depression on the posterior side of the distal femur that separates the medial and lateral condyles
intermediate cuneiform	middle of the three cuneiform tarsal bones; articulates posteriorly with the navicular bone, medially with the medial cuneiform bone, laterally with the lateral cuneiform bone, and anteriorly with the second metatarsal bone
interosseous border of the fibula	small ridge running down the medial side of the fibular shaft; for attachment of the interosseous membrane between the fibula and tibia
interosseous border of the tibia	small ridge running down the lateral side of the tibial shaft; for attachment of the interosseous membrane between the tibia and fibula
interosseous membrane of the leg	sheet of dense connective tissue that unites the shafts of the tibia and fibula bones
intertrochanteric crest	short, prominent ridge running between the greater and lesser trochanters on the posterior side of the proximal femur
intertrochanteric line	small ridge running between the greater and lesser trochanters on the anterior side of the proximal femur
knee joint	joint that separates the thigh and leg portions of the lower limb; formed by the articulations between the medial and lateral condyles of the femur, and the medial and lateral condyles of the tibia
lateral condyle of the femur	smooth, articulating surface that forms the distal and posterior sides of the lateral expansion of the distal femur
lateral condyle of the tibia	lateral, expanded region of the proximal tibia that includes the smooth surface that articulates with the lateral condyle of the femur as part of the knee joint
lateral cuneiform	most lateral of the three cuneiform tarsal bones; articulates posteriorly with the navicular bone, medially with the intermediate cuneiform bone, laterally with the cuboid bone, and anteriorly with the third metatarsal bone
lateral epicondyle of the femur	roughened area of the femur located on the lateral side of the lateral condyle
lateral malleolus	expanded distal end of the fibula
leg	portion of the lower limb located between the knee and ankle joints
lesser trochanter	small, bony projection on the medial side of the proximal femur, at the base of the femoral neck
ligament of the head of the femur	ligament that spans the acetabulum of the hip bone and the fovea capitis of the femoral head
linea aspera	longitudinally running bony ridge located in the middle third of the posterior femur
medial condyle of the femur	smooth, articulating surface that forms the distal and posterior sides of the medial expansion of the distal femur
medial condyle of the tibia	medial, expanded region of the proximal tibia that includes the smooth surface that articulates with the medial condyle of the femur as part of the knee joint
medial cuneiform	most medial of the three cuneiform tarsal bones; articulates posteriorly with the navicular bone, laterally with the intermediate cuneiform bone, and anteriorly with the first and second metatarsal bones
medial epicondyle of the femur	roughened area of the distal femur located on the medial side of the medial condyle
medial malleolus	bony expansion located on the medial side of the distal tibia
metatarsal bone	one of the five elongated bones that forms the anterior half of the foot; numbered 1–5, starting on the medial side of the foot
metatarsophalangeal joint	articulation between a metatarsal bone of the foot and the proximal phalanx bone of a toe
navicular	tarsal bone that articulates posteriorly with the talus bone, laterally with the cuboid bone, and anteriorly with the medial, intermediate, and lateral cuneiform bones
neck of the femur	narrowed region located inferior to the head of the femur
patella	kneecap; the largest sesamoid bone of the body; articulates with the distal femur
patellar surface	smooth groove located on the anterior side of the distal femur, between the medial and lateral condyles; site of articulation for the patella
phalanx bone of the foot	(plural = phalanges) one of the 14 bones that form the toes; these include the proximal and distal phalanges of the big toe, and the proximal, middle, and distal phalanx bones of toes two through five
proximal tibiofibular joint	articulation between the head of the fibula and the inferior aspect of the lateral condyle of the tibia
shaft of the femur	cylindrically shaped region that forms the central portion of the femur
shaft of the fibula	elongated, slender portion located between the expanded ends of the fibula
shaft of the tibia	triangular-shaped, central portion of the tibia
soleal line	small, diagonally running ridge located on the posterior side of the proximal tibia
sustentaculum tali	bony ledge extending from the medial side of the calcaneus bone
talus	tarsal bone that articulates superiorly with the tibia and fibula at the ankle joint; also articulates inferiorly with the calcaneus bone and anteriorly with the navicular bone
tarsal bone	one of the seven bones that make up the posterior foot; includes the calcaneus, talus, navicular, cuboid, medial cuneiform, intermediate cuneiform, and lateral cuneiform bones
thigh	portion of the lower limb located between the hip and knee joints
tibia	shin bone; the large, weight-bearing bone located on the medial side of the leg
apical ectodermal ridge	enlarged ridge of ectoderm at the distal end of a limb bud that stimulates growth and elongation of the limb
amphiarthrosis	slightly mobile joint
articulation	joint of the body
biaxial joint	type of diarthrosis; a joint that allows for movements within two planes (two axes)
cartilaginous joint	joint at which the bones are united by hyaline cartilage (synchondrosis) or fibrocartilage (symphysis)
diarthrosis	freely mobile joint
fibrous joint	joint where the articulating areas of the adjacent bones are connected by fibrous connective tissue
joint	site at which two or more bones or bone and cartilage come together (articulate)
joint cavity	space enclosed by the articular capsule of a synovial joint that is filled with synovial fluid and contains the articulating surfaces of the adjacent bones
multiaxial joint	type of diarthrosis; a joint that allows for movements within three planes (three axes)
synarthrosis	immobile or nearly immobile joint
synovial joint	joint at which the articulating surfaces of the bones are located within a joint cavity formed by an articular capsule
uniaxial joint	type of diarthrosis; joint that allows for motion within only one plane (one axis)
fontanelles	expanded areas of fibrous connective tissue that separate the braincase bones of the skull prior to birth and during the first year after birth
gomphosis	type of fibrous joint in which the root of a tooth is anchored into its bony jaw socket by strong periodontal ligaments
interosseous membrane	wide sheet of fibrous connective tissue that fills the gap between two parallel bones, forming a syndesmosis; found between the radius and ulna of the forearm and between the tibia and fibula of the leg
ligament	strong band of dense connective tissue spanning between bones
periodontal ligament	band of dense connective tissue that anchors the root of a tooth into the bony jaw socket
suture	fibrous joint that connects the bones of the skull (except the mandible); an immobile joint (synarthrosis)
syndesmosis	type of fibrous joint in which two separated, parallel bones are connected by an interosseous membrane
synostosis	site at which adjacent bones or bony components have fused together
symphysis	type of cartilaginous joint where the bones are joined by fibrocartilage
synchondrosis	type of cartilaginous joint where the bones are joined by hyaline cartilage
articular capsule	connective tissue structure that encloses the joint cavity of a synovial joint
articular cartilage	thin layer of hyaline cartilage that covers the articulating surfaces of bones at a synovial joint
articular disc	meniscus; a fibrocartilage structure found between the bones of some synovial joints; provides padding or smooths movements between the bones; strongly unites the bones together
ball-and-socket joint	synovial joint formed between the spherical end of one bone (the ball) that fits into the depression of a second bone (the socket); found at the hip and shoulder joints; functionally classified as a multiaxial joint
bursa	connective tissue sac containing lubricating fluid that prevents friction between adjacent structures, such as skin and bone, tendons and bone, or between muscles
condyloid joint	synovial joint in which the shallow depression at the end of one bone receives a rounded end from a second bone or a rounded structure formed by two bones; found at the metacarpophalangeal joints of the fingers or the radiocarpal joint of the wrist; functionally classified as a biaxial joint
extrinsic ligament	ligament located outside of the articular capsule of a synovial joint
hinge joint	synovial joint at which the convex surface of one bone articulates with the concave surface of a second bone; includes the elbow, knee, ankle, and interphalangeal joints; functionally classified as a uniaxial joint
intracapsular ligament	ligament that is located within the articular capsule of a synovial joint
intrinsic ligament	ligament that is fused to or incorporated into the wall of the articular capsule of a synovial joint
meniscus	articular disc
pivot joint	synovial joint at which the rounded portion of a bone rotates within a ring formed by a ligament and an articulating bone; functionally classified as uniaxial joint
plane joint	synovial joint formed between the flattened articulating surfaces of adjacent bones; functionally classified as a multiaxial joint
proximal radioulnar joint	articulation between head of radius and radial notch of ulna; uniaxial pivot joint that allows for rotation of radius during pronation/supination of forearm
saddle joint	synovial joint in which the articulating ends of both bones are convex and concave in shape, such as at the first carpometacarpal joint at the base of the thumb; functionally classified as a biaxial joint
subcutaneous bursa	bursa that prevents friction between skin and an underlying bone
submuscular bursa	bursa that prevents friction between bone and a muscle or between adjacent muscles
subtendinous bursa	bursa that prevents friction between bone and a muscle tendon
synovial fluid	thick, lubricating fluid that fills the interior of a synovial joint
synovial membrane	thin layer that lines the inner surface of the joint cavity at a synovial joint; produces the synovial fluid
tendon	dense connective tissue structure that anchors a muscle to bone
tendon sheath	connective tissue that surrounds a tendon at places where the tendon crosses a joint; contains a lubricating fluid to prevent friction and allow smooth movements of the tendon
abduction	movement in the coronal plane that moves a limb laterally away from the body; spreading of the fingers
adduction	movement in the coronal plane that moves a limb medially toward or across the midline of the body; bringing fingers together
circumduction	circular motion of the arm, thigh, hand, thumb, or finger that is produced by the sequential combination of flexion, abduction, extension, and adduction
depression	downward (inferior) motion of the scapula or mandible
dorsiflexion	movement at the ankle that brings the top of the foot toward the anterior leg
elevation	upward (superior) motion of the scapula or mandible
eversion	foot movement involving the intertarsal joints of the foot in which the bottom of the foot is turned laterally, away from the midline
extension	movement in the sagittal plane that increases the angle of a joint (straightens the joint); motion involving posterior bending of the vertebral column or returning to the upright position from a flexed position
flexion	movement in the sagittal plane that decreases the angle of a joint (bends the joint); motion involving anterior bending of the vertebral column
hyperextension	excessive extension of joint, beyond the normal range of movement
hyperflexion	excessive flexion of joint, beyond the normal range of movement
inferior rotation	movement of the scapula during upper limb adduction in which the glenoid cavity of the scapula moves in a downward direction as the medial end of the scapular spine moves in an upward direction
inversion	foot movement involving the intertarsal joints of the foot in which the bottom of the foot is turned toward the midline
lateral excursion	side-to-side movement of the mandible away from the midline, toward either the right or left side
lateral flexion	bending of the neck or body toward the right or left side
lateral (external) rotation	movement of the arm at the shoulder joint or the thigh at the hip joint that moves the anterior surface of the limb away from the midline of the body
medial excursion	side-to-side movement that returns the mandible to the midline
medial (internal) rotation	movement of the arm at the shoulder joint or the thigh at the hip joint that brings the anterior surface of the limb toward the midline of the body
opposition	thumb movement that brings the tip of the thumb in contact with the tip of a finger
plantar flexion	foot movement at the ankle in which the heel is lifted off of the ground
pronated position	forearm position in which the palm faces backward
pronation	forearm motion that moves the palm of the hand from the palm forward to the palm backward position
protraction	anterior motion of the scapula or mandible
reposition	movement of the thumb from opposition back to the anatomical position (next to index finger)
retraction	posterior motion of the scapula or mandible
rotation	movement of a bone around a central axis (atlantoaxial joint) or around its long axis (proximal radioulnar joint; shoulder or hip joint); twisting of the vertebral column resulting from the summation of small motions between adjacent vertebrae
superior rotation	movement of the scapula during upper limb abduction in which the glenoid cavity of the scapula moves in an upward direction as the medial end of the scapular spine moves in a downward direction
supinated position	forearm position in which the palm faces anteriorly (anatomical position)
supination	forearm motion that moves the palm of the hand from the palm backward to the palm forward position
acetabular labrum	lip of fibrocartilage that surrounds outer margin of the acetabulum on the hip bone
annular ligament	intrinsic ligament of the elbow articular capsule that surrounds and supports the head of the radius at the proximal radioulnar joint
anterior cruciate ligament	intracapsular ligament of the knee; extends from anterior, superior surface of the tibia to the inner aspect of the lateral condyle of the femur; resists hyperextension of knee
anterior talofibular ligament	intrinsic ligament located on the lateral side of the ankle joint, between talus bone and lateral malleolus of fibula; supports talus at the talocrural joint and resists excess inversion of the foot
atlantoaxial joint	series of three articulations between the atlas (C1) vertebra and the axis (C2) vertebra, consisting of the joints between the inferior articular processes of C1 and the superior articular processes of C2, and the articulation between the dens of C2 and the anterior arch of C1
atlanto-occipital joint	articulation between the occipital condyles of the skull and the superior articular processes of the atlas (C1 vertebra)
calcaneofibular ligament	intrinsic ligament located on the lateral side of the ankle joint, between the calcaneus bone and lateral malleolus of the fibula; supports the talus bone at the ankle joint and resists excess inversion of the foot
coracohumeral ligament	intrinsic ligament of the shoulder joint; runs from the coracoid process of the scapula to the anterior humerus
deltoid ligament	broad intrinsic ligament located on the medial side of the ankle joint; supports the talus at the talocrural joint and resists excess eversion of the foot
elbow joint	humeroulnar joint
femoropatellar joint	portion of the knee joint consisting of the articulation between the distal femur and the patella
fibular collateral ligament	extrinsic ligament of the knee joint that spans from the lateral epicondyle of the femur to the head of the fibula; resists hyperextension and rotation of the extended knee
glenohumeral joint	shoulder joint; articulation between the glenoid cavity of the scapula and head of the humerus; multiaxial ball-and-socket joint that allows for flexion/extension, abduction/adduction, circumduction, and medial/lateral rotation of the humerus
glenohumeral ligament	one of the three intrinsic ligaments of the shoulder joint that strengthen the anterior articular capsule
glenoid labrum	lip of fibrocartilage located around the outside margin of the glenoid cavity of the scapula
humeroradial joint	articulation between the capitulum of the humerus and head of the radius
humeroulnar joint	articulation between the trochlea of humerus and the trochlear notch of the ulna; uniaxial hinge joint that allows for flexion/extension of the forearm
iliofemoral ligament	intrinsic ligament spanning from the ilium of the hip bone to the femur, on the superior-anterior aspect of the hip joint
ischiofemoral ligament	intrinsic ligament spanning from the ischium of the hip bone to the femur, on the posterior aspect of the hip joint
lateral meniscus	C-shaped fibrocartilage articular disc located at the knee, between the lateral condyle of the femur and the lateral condyle of the tibia
lateral tibiofemoral joint	portion of the knee consisting of the articulation between the lateral condyle of the tibia and the lateral condyle of the femur; allows for flexion/extension at the knee
ligament of the head of the femur	intracapsular ligament that runs from the acetabulum of the hip bone to the head of the femur
medial meniscus	C-shaped fibrocartilage articular disc located at the knee, between the medial condyle of the femur and medial condyle of the tibia
medial tibiofemoral joint	portion of the knee consisting of the articulation between the medial condyle of the tibia and the medial condyle of the femur; allows for flexion/extension at the knee
patellar ligament	ligament spanning from the patella to the anterior tibia; serves as the final attachment for the quadriceps femoris muscle
posterior cruciate ligament	intracapsular ligament of the knee; extends from the posterior, superior surface of the tibia to the inner aspect of the medial condyle of the femur; prevents anterior displacement of the femur when the knee is flexed and weight bearing
posterior talofibular ligament	intrinsic ligament located on the lateral side of the ankle joint, between the talus bone and lateral malleolus of the fibula; supports the talus at the talocrural joint and resists excess inversion of the foot
pubofemoral ligament	intrinsic ligament spanning from the pubis of the hip bone to the femur, on the anterior-inferior aspect of the hip joint
radial collateral ligament	intrinsic ligament on the lateral side of the elbow joint; runs from the lateral epicondyle of humerus to merge with the annular ligament
rotator cuff	strong connective tissue structure formed by the fusion of four rotator cuff muscle tendons to the articular capsule of the shoulder joint; surrounds and supports superior, anterior, lateral, and posterior sides of the humeral head
subacromial bursa	bursa that protects the supraspinatus muscle tendon and superior end of the humerus from rubbing against the acromion of the scapula
subscapular bursa	bursa that prevents rubbing of the subscapularis muscle tendon against the scapula
subtalar joint	articulation between the talus and calcaneus bones of the foot; allows motions that contribute to inversion/eversion of the foot
talocrural joint	ankle joint; articulation between the talus bone of the foot and medial malleolus of the tibia, distal tibia, and lateral malleolus of the fibula; a uniaxial hinge joint that allows only for dorsiflexion and plantar flexion of the foot
temporomandibular joint (TMJ)	articulation between the condyle of the mandible and the mandibular fossa and articular tubercle of the temporal bone of the skull; allows for depression/elevation (opening/closing of mouth), protraction/retraction, and side-to-side motions of the mandible
tibial collateral ligament	extrinsic ligament of knee joint that spans from the medial epicondyle of the femur to the medial tibia; resists hyperextension and rotation of extended knee
ulnar collateral ligament	intrinsic ligament on the medial side of the elbow joint; spans from the medial epicondyle of the humerus to the medial ulna
zygapophysial joints	facet joints; plane joints between the superior and inferior articular processes of adjacent vertebrae that provide for only limited motions between the vertebrae
cardiac muscle	striated muscle found in the heart; joined to one another at intercalated discs and under the regulation of pacemaker cells, which contract as one unit to pump blood through the circulatory system. Cardiac muscle is under involuntary control.
contractility	ability to shorten (contract) forcibly
elasticity	ability to stretch and rebound
excitability	ability to undergo neural stimulation
extensibility	ability to lengthen (extend)
skeletal muscle	striated, multinucleated muscle that requires signaling from the nervous system to trigger contraction; most skeletal muscles are referred to as voluntary muscles that move bones and produce movement
smooth muscle	nonstriated, mononucleated muscle in the skin that is associated with hair follicles; assists in moving materials in the walls of internal organs, blood vessels, and internal passageways
acetylcholine (ACh)	neurotransmitter that binds at a motor end-plate to trigger depolarization
actin	protein that makes up most of the thin myofilaments in a sarcomere muscle fiber
action potential	change in voltage of a cell membrane in response to a stimulus that results in transmission of an electrical signal; unique to neurons and muscle fibers
aponeurosis	broad, tendon-like sheet of connective tissue that attaches a skeletal muscle to another skeletal muscle or to a bone
depolarize	to reduce the voltage difference between the inside and outside of a cell’s plasma membrane (the sarcolemma for a muscle fiber), making the inside less negative than at rest
endomysium	loose, and well-hydrated connective tissue covering each muscle fiber in a skeletal muscle
epimysium	outer layer of connective tissue around a skeletal muscle
excitation-contraction coupling	sequence of events from motor neuron signaling to a skeletal muscle fiber to contraction of the fiber’s sarcomeres
fascicle	bundle of muscle fibers within a skeletal muscle
motor end-plate	sarcolemma of muscle fiber at the neuromuscular junction, with receptors for the neurotransmitter acetylcholine
myofibril	long, cylindrical organelle that runs parallel within the muscle fiber and contains the sarcomeres
myosin	protein that makes up most of the thick cylindrical myofilament within a sarcomere muscle fiber
neuromuscular junction (NMJ)	synapse between the axon terminal of a motor neuron and the section of the membrane of a muscle fiber with receptors for the acetylcholine released by the terminal
neurotransmitter	signaling chemical released by nerve terminals that bind to and activate receptors on target cells
perimysium	connective tissue that bundles skeletal muscle fibers into fascicles within a skeletal muscle
sarcomere	longitudinally, repeating functional unit of skeletal muscle, with all of the contractile and associated proteins involved in contraction
sarcolemma	plasma membrane of a skeletal muscle fiber
sarcoplasm	cytoplasm of a muscle cell
sarcoplasmic reticulum (SR)	specialized smooth endoplasmic reticulum, which stores, releases, and retrieves Ca⁺⁺
synaptic cleft	space between a nerve (axon) terminal and a motor end-plate
T-tubule	projection of the sarcolemma into the interior of the cell
thick filament	the thick myosin strands and their multiple heads projecting from the center of the sarcomere toward, but not all to way to, the Z-discs
thin filament	thin strands of actin and its troponin-tropomyosin complex projecting from the Z-discs toward the center of the sarcomere
triad	the grouping of one T-tubule and two terminal cisternae
troponin	regulatory protein that binds to actin, tropomyosin, and calcium
tropomyosin	regulatory protein that covers myosin-binding sites to prevent actin from binding to myosin
voltage-gated sodium channels	membrane proteins that open sodium channels in response to a sufficient voltage change, and initiate and transmit the action potential as Na⁺ enters through the channel
aerobic respiration	production of ATP in the presence of oxygen
ATPase	enzyme that hydrolyzes ATP to ADP
creatine phosphate	phosphagen used to store energy from ATP and transfer it to muscle
glycolysis	anaerobic breakdown of glucose to ATP
lactic acid	product of anaerobic glycolysis
oxygen debt	amount of oxygen needed to compensate for ATP produced without oxygen during muscle contraction
power stroke	action of myosin pulling actin inward (toward the M line)
pyruvic acid	product of glycolysis that can be used in aerobic respiration or converted to lactic acid
fast glycolytic (FG)	muscle fiber that primarily uses anaerobic glycolysis
fast oxidative (FO)	intermediate muscle fiber that is between slow oxidative and fast glycolytic fibers
slow oxidative (SO)	muscle fiber that primarily uses aerobic respiration
abduct	move away from midline in the sagittal plane
agonist	(also, prime mover) muscle whose contraction is responsible for producing a particular motion
antagonist	muscle that opposes the action of an agonist
belly	bulky central body of a muscle
bipennate	pennate muscle that has fascicles that are located on both sides of the tendon
circular	(also, sphincter) fascicles that are concentrically arranged around an opening
convergent	fascicles that extend over a broad area and converge on a common attachment site
fascicle	muscle fibers bundled by perimysium into a unit
fixator	synergist that assists an agonist by preventing or reducing movement at another joint, thereby stabilizing the origin of the agonist
flexion	movement that decreases the angle of a joint
fusiform	muscle that has fascicles that are spindle-shaped to create large bellies
insertion	end of a skeletal muscle that is attached to the structure (usually a bone) that is moved when the muscle contracts
multipennate	pennate muscle that has a tendon branching within it
origin	end of a skeletal muscle that is attached to another structure (usually a bone) in a fixed position
parallel	fascicles that extend in the same direction as the long axis of the muscle
pennate	fascicles that are arranged differently based on their angles to the tendon
prime mover	(also, agonist) principle muscle involved in an action
synergist	muscle whose contraction helps a prime mover in an action
unipennate	pennate muscle that has fascicles located on one side of the tendon
abductor	moves the bone away from the midline
adductor	moves the bone toward the midline
bi	two
brevis	short
extensor	muscle that increases the angle at the joint
flexor	muscle that decreases the angle at the joint
lateralis	to the outside
longus	long
maximus	largest
medialis	to the inside
medius	medium
minimus	smallest
oblique	at an angle
rectus	straight
tri	three
anterior scalene	a muscle anterior to the middle scalene
appendicular	of the arms and legs
axial	of the trunk and head
buccinator	muscle that compresses the cheek
corrugator supercilii	prime mover of the eyebrows
deglutition	swallowing
digastric	muscle that has anterior and posterior bellies and elevates the hyoid bone and larynx when one swallows; it also depresses the mandible
epicranial aponeurosis	(also, galea aponeurosis) flat broad tendon that connects the frontalis and occipitalis
erector spinae group	large muscle mass of the back; primary extensor of the vertebral column
extrinsic eye muscles	originate outside the eye and insert onto the outer surface of the white of the eye, and create eyeball movement
frontalis	front part of the occipitofrontalis muscle
genioglossus	muscle that originates on the mandible and allows the tongue to move downward and forward
geniohyoid	muscle that depresses the mandible, and raises and pulls the hyoid bone anteriorly
hyoglossus	muscle that originates on the hyoid bone to move the tongue downward and flatten it
iliocostalis cervicis	muscle of the iliocostalis group associated with the cervical region
iliocostalis group	laterally placed muscles of the erector spinae
iliocostalis lumborum	muscle of the iliocostalis group associated with the lumbar region
iliocostalis thoracis	muscle of the iliocostalis group associated with the thoracic region
infrahyoid muscles	anterior neck muscles that are attached to, and inferior to the hyoid bone
lateral pterygoid	muscle that moves the mandible from side to side
longissimus capitis	muscle of the longissimus group associated with the head region
longissimus cervicis	muscle of the longissimus group associated with the cervical region
longissimus group	intermediately placed muscles of the erector spinae
longissimus thoracis	muscle of the longissimus group associated with the thoracic region
masseter	main muscle for chewing that elevates the mandible to close the mouth
mastication	chewing
medial pterygoid	muscle that moves the mandible from side to side
middle scalene	longest scalene muscle, located between the anterior and posterior scalenes
multifidus	muscle of the lumbar region that helps extend and laterally flex the vertebral column
mylohyoid	muscle that lifts the hyoid bone and helps press the tongue to the top of the mouth
occipitalis	posterior part of the occipitofrontalis muscle
occipitofrontalis	muscle that makes up the scalp with a frontal belly and an occipital belly
omohyoid	muscle that has superior and inferior bellies and depresses the hyoid bone
orbicularis oculi	circular muscle that closes the eye
orbicularis oris	circular muscle that moves the lips
palatoglossus	muscle that originates on the soft palate to elevate the back of the tongue
posterior scalene	smallest scalene muscle, located posterior to the middle scalene
scalene muscles	flex, laterally flex, and rotate the head; contribute to deep inhalation
segmental muscle group	interspinales and intertransversarii muscles that bring together the spinous and transverse processes of each consecutive vertebra
semispinalis capitis	transversospinales muscle associated with the head region
semispinalis cervicis	transversospinales muscle associated with the cervical region
semispinalis thoracis	transversospinales muscle associated with the thoracic region
spinalis capitis	muscle of the spinalis group associated with the head region
spinalis cervicis	muscle of the spinalis group associated with the cervical region
spinalis group	medially placed muscles of the erector spinae
spinalis thoracis	muscle of the spinalis group associated with the thoracic region
splenius	posterior neck muscles; includes the splenius capitis and splenius cervicis
splenius capitis	neck muscle that inserts into the head region
splenius cervicis	neck muscle that inserts into the cervical region
sternocleidomastoid	major muscle that laterally flexes and rotates the head
sternohyoid	muscle that depresses the hyoid bone
sternothyroid	muscle that depresses the larynx’s thyroid cartilage
styloglossus	muscle that originates on the styloid bone, and allows upward and backward motion of the tongue
stylohyoid	muscle that elevates the hyoid bone posteriorly
suprahyoid muscles	neck muscles that are superior to the hyoid bone
temporalis	muscle that retracts the mandible
thyrohyoid	muscle that depresses the hyoid bone and elevates the larynx’s thyroid cartilage
transversospinales	muscles that originate at the transverse processes and insert at the spinous processes of the vertebrae
anal triangle	posterior triangle of the perineum that includes the anus
caval opening	opening in the diaphragm that allows the inferior vena cava to pass through; foramen for the vena cava
compressor urethrae	deep perineal muscle in women
deep transverse perineal	deep perineal muscle in men
diaphragm	skeletal muscle that separates the thoracic and abdominal cavities and is dome-shaped at rest
external intercostal	superficial intercostal muscles that raise the rib cage
external oblique	superficial abdominal muscle with fascicles that extend inferiorly and medially
iliococcygeus	muscle that makes up the levator ani along with the pubococcygeus
innermost intercostal	the deepest intercostal muscles that draw the ribs together
intercostal muscles	muscles that span the spaces between the ribs
internal intercostal	muscles the intermediate intercostal muscles that draw the ribs together
internal oblique	flat, intermediate abdominal muscle with fascicles that run perpendicular to those of the external oblique
ischiococcygeus	muscle that assists the levator ani and pulls the coccyx anteriorly
levator ani	pelvic muscle that resists intra-abdominal pressure and supports the pelvic viscera
linea alba	white, fibrous band that runs along the midline of the trunk
pelvic diaphragm	muscular sheet that comprises the levator ani and the ischiococcygeus
perineum	diamond-shaped region between the pubic symphysis, coccyx, and ischial tuberosities
pubococcygeus	muscle that makes up the levator ani along with the iliococcygeus
quadratus lumborum	posterior part of the abdominal wall that helps with posture and stabilization of the body
rectus abdominis	long, linear muscle that extends along the middle of the trunk
rectus sheaths	tissue that makes up the linea alba
sphincter urethrovaginalis	deep perineal muscle in women
tendinous intersections	three transverse bands of collagen fibers that divide the rectus abdominis into segments
transversus abdominis	deep layer of the abdomen that has fascicles arranged transversely around the abdomen
urogenital triangle	anterior triangle of the perineum that includes the external genitals
abductor digiti minimi	muscle that abducts the little finger
adductor pollicis	muscle that adducts the thumb
abductor pollicis brevis	muscle that abducts the thumb
abductor pollicis longus	muscle that inserts into the first metacarpal
anconeus	small muscle on the lateral posterior elbow that extends the forearm
anterior compartment of the arm	(anterior flexor compartment of the arm) the biceps brachii, brachialis, brachioradialis, and their associated blood vessels and nerves
anterior compartment of the forearm	(anterior flexor compartment of the forearm) deep and superficial muscles that originate on the humerus and insert into the hand
biceps brachii	two-headed muscle that crosses the shoulder and elbow joints to flex the forearm while assisting in supinating it and flexing the arm at the shoulder
brachialis	muscle deep to the biceps brachii that provides power in flexing the forearm.
brachioradialis	muscle that can flex the forearm quickly or help lift a load slowly
coracobrachialis	muscle that flexes and adducts the arm
deep anterior compartment	flexor pollicis longus, flexor digitorum profundus, and their associated blood vessels and nerves
deep posterior compartment of the forearm	(deep posterior extensor compartment of the forearm) the abductor pollicis longus, extensor pollicis brevis, extensor pollicis longus, extensor indicis, and their associated blood vessels and nerves
deltoid	shoulder muscle that abducts the arm as well as flexes and medially rotates it, and extends and laterally rotates it
dorsal interossei	muscles that abduct and flex the three middle fingers at the metacarpophalangeal joints and extend them at the interphalangeal joints
extensor carpi radialis brevis	muscle that extends and abducts the hand at the wrist
extensor carpi ulnaris	muscle that extends and adducts the hand
extensor digiti minimi	muscle that extends the little finger
extensor digitorum	muscle that extends the hand at the wrist and the phalanges
extensor indicis	muscle that inserts onto the tendon of the extensor digitorum of the index finger
extensor pollicis brevis	muscle that inserts onto the base of the proximal phalanx of the thumb
extensor pollicis longus	muscle that inserts onto the base of the distal phalanx of the thumb
extensor radialis longus	muscle that extends and abducts the hand at the wrist
extensor retinaculum	band of connective tissue that extends over the dorsal surface of the hand
extrinsic muscles of the hand	muscles that move the wrists, hands, and fingers and originate on the arm
flexor carpi radialis	muscle that flexes and abducts the hand at the wrist
flexor carpi ulnaris	muscle that flexes and adducts the hand at the wrist
flexor digiti minimi brevis	muscle that flexes the little finger
flexor digitorum profundus	muscle that flexes the phalanges of the fingers and the hand at the wrist
flexor digitorum superficialis	muscle that flexes the hand and the digits
flexor pollicis brevis	muscle that flexes the thumb
flexor pollicis longus	muscle that flexes the distal phalanx of the thumb
flexor retinaculum	band of connective tissue that extends over the palmar surface of the hand
hypothenar	group of muscles on the medial aspect of the palm
hypothenar eminence	rounded contour of muscle at the base of the little finger
infraspinatus	muscle that laterally rotates the arm
intermediate	group of midpalmar muscles
intrinsic muscles of the hand	muscles that move the wrists, hands, and fingers and originate in the palm
latissimus dorsi	broad, triangular axial muscle located on the inferior part of the back
lumbrical	muscle that flexes each finger at the metacarpophalangeal joints and extend each finger at the interphalangeal joints
opponens digiti minimi	muscle that brings the little finger across the palm to meet the thumb
opponens pollicis	muscle that moves the thumb across the palm to meet another finger
palmar interossei	muscles that abduct and flex each finger at the metacarpophalangeal joints and extend each finger at the interphalangeal joints
palmaris longus	muscle that provides weak flexion of the hand at the wrist
pectoral girdle	shoulder girdle, made up of the clavicle and scapula
pectoralis major	thick, fan-shaped axial muscle that covers much of the superior thorax
pectoralis minor	muscle that moves the scapula and assists in inhalation
pronator quadratus	pronator that originates on the ulna and inserts on the radius
pronator teres	pronator that originates on the humerus and inserts on the radius
retinacula	fibrous bands that sheath the tendons at the wrist
rhomboid major	muscle that attaches the vertebral border of the scapula to the spinous process of the thoracic vertebrae
rhomboid minor	muscle that attaches the vertebral border of the scapula to the spinous process of the thoracic vertebrae
rotator cuff	(also, musculotendinous cuff) the circle of tendons around the shoulder joint
serratus anterior	large and flat muscle that originates on the ribs and inserts onto the scapula
subclavius	muscle that stabilizes the clavicle during movement
subscapularis	muscle that originates on the anterior scapula and medially rotates the arm
superficial anterior compartment of the forearm	flexor carpi radialis, palmaris longus, flexor carpi ulnaris, flexor digitorum superficialis, and their associated blood vessels and nerves
superficial posterior compartment of the forearm	extensor radialis longus, extensor carpi radialis brevis, extensor digitorum, extensor digiti minimi, extensor carpi ulnaris, and their associated blood vessels and nerves
supinator	muscle that moves the palm and forearm anteriorly
supraspinatus	muscle that abducts the arm
teres major	muscle that extends the arm and assists in adduction and medial rotation of it
teres minor	muscle that laterally rotates and extends the arm
thenar	group of muscles on the lateral aspect of the palm
thenar eminence	rounded contour of muscle at the base of the thumb
trapezius	muscle that stabilizes the upper part of the back
triceps brachii	three-headed muscle that extends the forearm
adductor brevis	muscle that adducts and medially rotates the thigh
adductor longus	muscle that adducts, medially rotates, and flexes the thigh
adductor magnus	muscle with an anterior fascicle that adducts, medially rotates and flexes the thigh, and a posterior fascicle that assists in thigh extension
anterior compartment of the leg	region that includes muscles that dorsiflex the foot
anterior compartment of the thigh	region that includes muscles that flex the thigh and extend the leg
biceps femoris	hamstring muscle
calcaneal tendon	(also, Achilles tendon) strong tendon that inserts into the calcaneal bone of the ankle
dorsal group	region that includes the extensor digitorum brevis
extensor digitorum brevis	muscle that extends the toes
extensor digitorum longus	muscle that is lateral to the tibialis anterior
extensor hallucis longus	muscle that is partly deep to the tibialis anterior and extensor digitorum longus
femoral triangle	region formed at the junction between the hip and the leg and includes the pectineus, femoral nerve, femoral artery, femoral vein, and deep inguinal lymph nodes
fibularis brevis	(also, peroneus brevis) muscle that plantar flexes the foot at the ankle and everts it at the intertarsal joints
fibularis longus	(also, peroneus longus) muscle that plantar flexes the foot at the ankle and everts it at the intertarsal joints
fibularis tertius	small muscle that is associated with the extensor digitorum longus
flexor digitorum longus	muscle that flexes the four small toes
flexor hallucis longus	muscle that flexes the big toe
gastrocnemius	most superficial muscle of the calf
gluteal group	muscle group that extends, flexes, rotates, adducts, and abducts the femur
gluteus maximus	largest of the gluteus muscles that extends the femur
gluteus medius	muscle deep to the gluteus maximus that abducts the femur at the hip
gluteus minimus	smallest of the gluteal muscles and deep to the gluteus medius
gracilis	muscle that adducts the thigh and flexes the leg at the knee
hamstring group	three long muscles on the back of the leg
iliacus	muscle that, along with the psoas major, makes up the iliopsoas
iliopsoas group	muscle group consisting of iliacus and psoas major muscles, that flexes the thigh at the hip, rotates it laterally, and flexes the trunk of the body onto the hip
iliotibial tract	muscle that inserts onto the tibia; made up of the gluteus maximus and connective tissues of the tensor fasciae latae
inferior extensor retinaculum	cruciate ligament of the ankle
inferior gemellus	muscle deep to the gluteus maximus on the lateral surface of the thigh that laterally rotates the femur at the hip
lateral compartment of the leg	region that includes the fibularis (peroneus) longus and the fibularis (peroneus) brevis and their associated blood vessels and nerves
medial compartment of the thigh	a region that includes the adductor longus, adductor brevis, adductor magnus, pectineus, gracilis, and their associated blood vessels and nerves
obturator externus	muscle deep to the gluteus maximus on the lateral surface of the thigh that laterally rotates the femur at the hip
obturator internus	muscle deep to the gluteus maximus on the lateral surface of the thigh that laterally rotates the femur at the hip
patellar ligament	extension of the quadriceps tendon below the patella
pectineus	muscle that abducts and flexes the femur at the hip
pelvic girdle	hips, a foundation for the lower limb
piriformis	muscle deep to the gluteus maximus on the lateral surface of the thigh that laterally rotates the femur at the hip
plantar aponeurosis	muscle that supports the longitudinal arch of the foot
plantar group	four-layered group of intrinsic foot muscles
plantaris	muscle that runs obliquely between the gastrocnemius and the soleus
popliteal fossa	diamond-shaped space at the back of the knee
popliteus	muscle that flexes the leg at the knee and creates the floor of the popliteal fossa
posterior compartment of the leg	region that includes the superficial gastrocnemius, soleus, and plantaris, and the deep popliteus, flexor digitorum longus, flexor hallucis longus, and tibialis posterior
posterior compartment of the thigh	region that includes muscles that flex the leg and extend the thigh
psoas major	muscle that, along with the iliacus, makes up the iliopsoas
quadratus femoris	muscle deep to the gluteus maximus on the lateral surface of the thigh that laterally rotates the femur at the hip
quadriceps femoris group	four muscles, that extend and stabilize the knee
quadriceps tendon	(also, patellar tendon) tendon common to all four quadriceps muscles, inserts into the patella
rectus femoris	quadricep muscle on the anterior aspect of the thigh
sartorius	band-like muscle that flexes, abducts, and laterally rotates the leg at the hip
semimembranosus	hamstring muscle
semitendinosus	hamstring muscle
soleus	wide, flat muscle deep to the gastrocnemius
superior extensor retinaculum	transverse ligament of the ankle
superior gemellus	muscle deep to the gluteus maximus on the lateral surface of the thigh that laterally rotates the femur at the hip
tensor fascia lata	muscle that flexes and abducts the thigh
tibialis anterior	muscle located on the lateral surface of the tibia
tibialis posterior	muscle that plantar flexes and inverts the foot
vastus intermedius	quadricep muscle that is between the vastus lateralis and vastus medialis and is deep to the rectus femoris
vastus lateralis	quadricep muscle on the lateral aspect of the thigh
vastus medialis	quadricep muscle on the medial aspect of the thigh
autonomic nervous system (ANS)	functional division of the nervous system that is responsible for homeostatic reflexes that coordinate control of cardiac and smooth muscle, as well as glandular tissue
axon	single process of the neuron that carries an electrical signal (action potential) away from the cell body toward a target cell
brain	the large organ of the central nervous system composed of white and gray matter, contained within the cranium and continuous with the spinal cord
central nervous system (CNS)	anatomical division of the nervous system located within the cranial and vertebral cavities, namely the brain and spinal cord
dendrite	one of many branchlike processes that extends from the neuron cell body and functions as a contact for incoming signals (synapses) from other neurons or sensory cells
enteric nervous system (ENS)	neural tissue associated with the digestive system that is responsible for nervous control through autonomic connections
ganglion	localized collection of neuron cell bodies in the peripheral nervous system
glial cell	one of the various types of neural tissue cells responsible for maintenance of the tissue, and largely responsible for supporting neurons
gray matter	regions of the nervous system containing cell bodies of neurons with few or no myelinated axons; actually may be more pink or tan in color, but called gray in contrast to white matter
integration	nervous system function that combines sensory perceptions and higher cognitive functions (memories, learning, emotion, etc.) to produce a response
myelin	lipid-rich insulating substance surrounding the axons of many neurons, allowing for faster transmission of electrical signals
nerve	cord-like bundle of axons located in the peripheral nervous system that transmits sensory input and response output to and from the central nervous system
neuron	neural tissue cell that is primarily responsible for generating and propagating electrical signals into, within, and out of the nervous system
nucleus	in the nervous system, a localized collection of neuron cell bodies that are functionally related; a “center” of neural function
peripheral nervous system (PNS)	anatomical division of the nervous system that is largely outside the cranial and vertebral cavities, namely all parts except the brain and spinal cord
process	in cells, an extension of a cell body; in the case of neurons, this includes the axon and dendrites
response	nervous system function that causes a target tissue (muscle or gland) to produce an event as a consequence to stimuli
sensation	nervous system function that receives information from the environment and translates it into the electrical signals of nervous tissue
soma	in neurons, that portion of the cell that contains the nucleus; the cell body, as opposed to the cell processes (axons and dendrites)
somatic nervous system (SNS)	functional division of the nervous system that is concerned with conscious perception, voluntary movement, and skeletal muscle reflexes
spinal cord	organ of the central nervous system found within the vertebral cavity and connected with the periphery through spinal nerves; mediates reflex behaviors
stimulus	an event in the external or internal environment that registers as activity in a sensory neuron
tract	bundle of axons in the central nervous system having the same function and point of origin
white matter	regions of the nervous system containing mostly myelinated axons, making the tissue appear white because of the high lipid content of myelin
astrocyte	glial cell type of the CNS that provides support for neurons and maintains the blood-brain barrier
axon hillock	tapering of the neuron cell body that gives rise to the axon
axon segment	single stretch of the axon insulated by myelin and bounded by nodes of Ranvier at either end (except for the first, which is after the initial segment, and the last, which is followed by the axon terminal)
axon terminal	end of the axon, where there are usually several branches extending toward the target cell
axoplasm	cytoplasm of an axon, which is different in composition than the cytoplasm of the neuronal cell body
bipolar	shape of a neuron with two processes extending from the neuron cell body—the axon and one dendrite
blood-brain barrier (BBB)	physiological barrier between the circulatory system and the central nervous system that establishes a privileged blood supply, restricting the flow of substances into the CNS
cerebrospinal fluid (CSF)	circulatory medium within the CNS that is produced by ependymal cells in the choroid plexus filtering the blood
choroid plexus	specialized structure containing ependymal cells that line blood capillaries and filter blood to produce CSF in the four ventricles of the brain
ependymal cell	glial cell type in the CNS responsible for producing cerebrospinal fluid
initial segment	first part of the axon as it emerges from the axon hillock, where the electrical signals known as action potentials are generated
interneuron	functional classification of a neuron that integrates information between sensory and motor neurons
microglia	glial cell type in the CNS that serves as the resident component of the immune system
motor neuron	functional classification of a neuron that carries commands from the brain and spinal cord to muscles and glands
multipolar	shape of a neuron that has multiple processes—the axon and two or more dendrites
myelin sheath	lipid-rich layer of insulation that surrounds an axon, formed by oligodendrocytes in the CNS and Schwann cells in the PNS; facilitates the transmission of electrical signals
neuronal polarity	asymmetrical distribution of cellular components (dendrites and axon) within a neuron
node of Ranvier	gap between two myelinated regions of an axon, allowing for strengthening of the electrical signal as it propagates down the axon
oligodendrocyte	glial cell type in the CNS that provides the myelin insulation for axons in tracts
satellite cell	glial cell type in the PNS that provides support for neurons in the ganglia
Schwann cell	glial cell type in the PNS that provides the myelin insulation for axons in nerves
sensory neuron	functional classification of a neuron that carries sensory information from the body's periphery into the nervous system
synapse	narrow junction across which a chemical signal passes from neuron to the next, initiating a new electrical signal in the target cell
synaptic end bulb	swelling at the end of an axon where neurotransmitter molecules are released onto a target cell across a synapse
unipolar	shape of a neuron which has only one process that includes both the axon and dendrite
ventricle	central cavity within the brain where CSF is produced and circulates
action potential	change in the electrical properties of a cell membrane in response to a stimulus that results in transmission of an electrical signal; unique to neurons and muscle fibers
All-or-None Law	the principle that the strength by which a neuron responds to a stimulus is not dependent on the strength of the stimulus;
cerebral cortex	outermost layer of gray matter in the brain, where conscious perception takes place
chemical synapse	connection between two neurons, or between a neuron and its target, where a neurotransmitter diffuses across a very short distance
continuous conduction	slower propagation of the action potential along an unmyelinated axon
electrical synapse	connection between two neurons, or any two electrically active cells, where an action potential can flow across gap junctions into the adjacent cell
lower motor neuron	second neuron in the motor command pathway that is directly connected to the skeletal muscle
neurotransmitter	chemical signal that is released from the synaptic end bulb of a neuron to cause a change in the target cell
postsynaptic cell	cell receiving a synapse from another cell
precentral gyrus of the frontal cortex	region of the cerebral cortex responsible for generating motor commands, where the upper motor neuron cell body is located
presynaptic cell	cell forming a synapse with another cell
propagation	movement of an action potential along the length of an axon
saltatory conduction	faster propagation of the action potential in a myelinated axon, from one node of Ranvier to the following node
synaptic cleft	small gap between cells in a chemical synapse where neurotransmitter diffuses from the presynaptic element to the postsynaptic element
thalamus	region of the central nervous system that acts as a relay for sensory pathways
thermoreceptor	type of sensory receptor capable of transducing temperature stimuli into neural action potentials
threshold	membrane voltage at which an action potential is initiated
upper motor neuron	first neuron in the motor command pathway with its cell body in the cerebral cortex that synapses on the lower motor neuron in the spinal cord
brain stem	region of the adult brain that includes the midbrain, pons, and medulla oblongata and develops from the mesencephalon, metencephalon, and myelencephalon of the embryonic brain
cephalic flexure	curve in midbrain of the embryo that positions the forebrain ventrally
diencephalon	region of the adult brain that retains its name from embryonic development and includes the thalamus and hypothalamus
forebrain	anterior region of the adult brain that develops from the prosencephalon and includes the cerebrum and diencephalon
hindbrain	posterior region of the adult brain that develops from the rhombencephalon and includes the pons, medulla oblongata, and cerebellum
mesencephalon	primary vesicle of the embryonic brain that does not significantly change through the rest of embryonic development and becomes the midbrain
metencephalon	secondary vesicle of the embryonic brain that develops into the pons and the cerebellum
midbrain	middle region of the adult brain that develops from the mesencephalon
myelencephalon	secondary vesicle of the embryonic brain that develops into the medulla
neural crest	tissue that detaches from the edges of the neural groove and migrates through the embryo to develop into peripheral structures of both nervous and non-nervous tissues
neural fold	elevated edge of the neural groove
neural groove	region of the neural plate that folds into the dorsal surface of the embryo and closes off to become the neural tube
neural plate	thickened layer of neuroepithelium that runs longitudinally along the dorsal surface of an embryo and gives rise to nervous system tissue
neural tube	precursor to structures of the central nervous system, formed by the invagination and separation of neuroepithelium
neuraxis	central axis to the nervous system, from the posterior to anterior ends of the neural tube; the inferior tip of the spinal cord to the anterior surface of the cerebrum
primary vesicle	initial enlargements of the anterior neural tube during embryonic development that develop into the forebrain, midbrain, and hindbrain
prosencephalon	primary vesicle of the embryonic brain that develops into the forebrain, which includes the cerebrum and diencephalon
rhombencephalon	primary vesicle of the embryonic brain that develops into the hindbrain, which includes the pons, cerebellum, and medulla
secondary vesicle	five vesicles that develop from primary vesicles, continuing the process of differentiation of the embryonic brain
telencephalon	secondary vesicle of the embryonic brain that develops into the cerebrum
anterior spinal artery	blood vessel from the merged branches of the vertebral arteries that runs along the anterior surface of the spinal cord
arachnoid granulation	outpocket of the arachnoid membrane into the dural sinuses that allows for reabsorption of CSF into the blood
arachnoid mater	middle layer of the meninges named for the spider-web–like trabeculae that extend between it and the pia mater
arachnoid trabeculae	filaments between the arachnoid and pia mater within the subarachnoid space
basilar artery	blood vessel from the merged vertebral arteries that runs along the dorsal surface of the brain stem
carotid canal	opening in the temporal bone through which the internal carotid artery enters the cranium
central canal	hollow space within the spinal cord that is the remnant of the center of the neural tube
cerebral aqueduct	connection of the ventricular system between the third and fourth ventricles located in the midbrain
choroid plexus	specialized structures containing ependymal cells lining blood capillaries that filter blood to produce CSF in the four ventricles of the brain
circle of Willis	unique anatomical arrangement of blood vessels around the base of the brain that maintains perfusion of blood into the brain even if one component of the structure is blocked or narrowed
common carotid artery	blood vessel that branches off the aorta (or the brachiocephalic artery on the right) and supplies blood to the head and neck
dura mater	tough, fibrous, outer layer of the meninges that is attached to the inner surface of the cranium and vertebral column and surrounds the entire CNS
dural sinus	any of the venous structures surrounding the brain, enclosed within the dura mater, which drain blood from the CNS to the common venous return of the jugular veins
foramen magnum	large opening in the occipital bone of the skull through which the spinal cord emerges and the vertebral arteries enter the cranium
fourth ventricle	the portion of the ventricular system that is in the region of the brain stem and opens into the subarachnoid space through the median and lateral apertures
internal carotid artery	branch from the common carotid artery that enters the cranium and supplies blood to the brain
interventricular foramina	openings between the lateral ventricles and third ventricle allowing for the passage of CSF
jugular veins	blood vessels that return “used” blood from the head and neck
lateral apertures	pair of openings from the fourth ventricle to the subarachnoid space on either side and between the medulla and cerebellum
lateral ventricles	portions of the ventricular system that are in the region of the cerebrum
lumbar puncture	procedure used to withdraw CSF from the lower lumbar region of the vertebral column that avoids the risk of damaging CNS tissue because the spinal cord ends at the upper lumbar vertebrae
median aperture	singular opening from the fourth ventricle into the subarachnoid space at the midline between the medulla and cerebellum
meninges	protective outer coverings of the CNS composed of connective tissue
occipital sinuses	dural sinuses along the edge of the occipital lobes of the cerebrum
orthostatic reflex	sympathetic function that maintains blood pressure when standing to offset the increased effect of gravity
pia mater	thin, innermost membrane of the meninges that directly covers the surface of the CNS
sigmoid sinuses	dural sinuses that drain directly into the jugular veins
straight sinus	dural sinus that drains blood from the deep center of the brain to collect with the other sinuses
subarachnoid space	space between the arachnoid mater and pia mater that contains CSF and the fibrous connections of the arachnoid trabeculae
superior sagittal sinus	dural sinus that runs along the top of the longitudinal fissure and drains blood from the majority of the outer cerebrum
third ventricle	portion of the ventricular system that is in the region of the diencephalon
transverse sinuses	dural sinuses that drain along either side of the occipital–cerebellar space
ventricles	remnants of the hollow center of the neural tube that are spaces for cerebrospinal fluid to circulate through the brain
amygdala	nucleus deep in the temporal lobe of the cerebrum that is related to memory and emotional behavior
ascending tract	central nervous system fibers carrying sensory information from the spinal cord or periphery to the brain
ataxia	movement disorder related to damage of the cerebellum characterized by loss of coordination in voluntary movements
basal forebrain	nuclei of the cerebrum related to modulation of sensory stimuli and attention through broad projections to the cerebral cortex, loss of which is related to Alzheimer’s disease
basal nuclei	nuclei of the cerebrum (with a few components in the upper brain stem and diencephalon) that are responsible for assessing cortical movement commands and comparing them with the general state of the individual through broad modulatory activity of dopamine neurons; largely related to motor functions, as evidenced through the symptoms of Parkinson’s and Huntington’s diseases
Broca’s area	region of the frontal lobe associated with the motor commands necessary for speech production and located only in the cerebral hemisphere responsible for language production, which is the left side in approximately 95 percent of the population
Brodmann’s areas	mapping of regions of the cerebral cortex based on microscopic anatomy that relates specific areas to functional differences, as described by Brodmann in the early 1900s
caudate	nucleus deep in the cerebrum that is part of the basal nuclei; along with the putamen, it is part of the striatum
central sulcus	surface landmark of the cerebral cortex that marks the boundary between the frontal and parietal lobes
cerebral cortex	outer gray matter covering the forebrain, marked by wrinkles and folds known as gyri and sulci
cerebrum	region of the adult brain that develops from the telencephalon and is responsible for higher neurological functions such as memory, emotion, and consciousness
cerebellum	region of the adult brain connected primarily to the pons that developed from the metencephalon (along with the pons) and is largely responsible for comparing information from the cerebrum with sensory feedback from the periphery through the spinal cord
cerebral hemisphere	one half of the bilaterally symmetrical cerebrum
corpus callosum	large white matter structure that connects the right and left cerebral hemispheres
descending tract	central nervous system fibers carrying motor commands from the brain to the spinal cord or periphery
direct pathway	connections within the basal nuclei from the striatum to the globus pallidus internal segment and substantia nigra pars reticulata that disinhibit the thalamus to increase cortical control of movement
disinhibition	disynaptic connection in which the first synapse inhibits the second cell, which then stops inhibiting the final target
epithalamus	region of the diecephalon containing the pineal gland
frontal eye field	region of the frontal lobe associated with motor commands to orient the eyes toward an object of visual attention
frontal lobe	region of the cerebral cortex directly beneath the frontal bone of the cranium
gait	rhythmic pattern of alternating movements of the lower limbs during locomotion
globus pallidus	nuclei deep in the cerebrum that are part of the basal nuclei and can be divided into the internal and external segments
gyrus	ridge formed by convolutions on the surface of the cerebrum or cerebellum
hippocampus	gray matter deep in the temporal lobe that is very important for long-term memory formation
hypothalamus	major region of the diencephalon that is responsible for coordinating autonomic and endocrine control of homeostasis
indirect pathway	connections within the basal nuclei from the striatum through the globus pallidus external segment and subthalamic nucleus to the globus pallidus internal segment/substantia nigra pars compacta that result in inhibition of the thalamus to decrease cortical control of movement
inferior cerebellar peduncle (ICP)	input to the cerebellum, largely from the inferior olive, that represents sensory feedback from the periphery
inferior colliculus	half of the midbrain tectum that is part of the brain stem auditory pathway
inferior olive	nucleus in the medulla that is involved in processing information related to motor control
kinesthesia	general sensory perception of movement of the body
lateral sulcus	surface landmark of the cerebral cortex that marks the boundary between the temporal lobe and the frontal and parietal lobes
limbic cortex	collection of structures of the cerebral cortex that are involved in emotion, memory, and behavior and are part of the larger limbic system
limbic system	structures at the edge (limit) of the boundary between the forebrain and hindbrain that are most associated with emotional behavior and memory formation
longitudinal fissure	large separation along the midline between the two cerebral hemispheres
middle cerebellar peduncle (MCP)	large, white-matter bridge from the pons that constitutes the major input to the cerebellar cortex
occipital lobe	region of the cerebral cortex directly beneath the occipital bone of the cranium
olfaction	special sense responsible for smell, which has a unique, direct connection to the cerebrum
parietal lobe	region of the cerebral cortex directly beneath the parietal bone of the cranium
parieto-occipital sulcus	groove in the cerebral cortex representing the border between the parietal and occipital cortices
postcentral gyrus	ridge just posterior to the central sulcus, in the parietal lobe, where somatosensory processing initially takes place in the cerebrum
precentral gyrus	primary motor cortex located in the frontal lobe of the cerebral cortex
prefrontal lobe	specific region of the frontal lobe anterior to the more specific motor function areas, which can be related to the early planning of movements and intentions to the point of being personality-type functions
premotor area	region of the frontal lobe responsible for planning movements that will be executed through the primary motor cortex
proprioception	general sensory perceptions providing information about location and movement of body parts; the “sense of the self”
putamen	nucleus deep in the cerebrum that is part of the basal nuclei; along with the caudate, it is part of the striatum
reticular formation	diffuse region of gray matter throughout the brain stem that regulates sleep, wakefulness, and states of consciousness
somatosensation	general senses related to the body, usually thought of as the senses of touch, which would include pain, temperature, and proprioception
striatum	the caudate and putamen collectively, as part of the basal nuclei, which receive input from the cerebral cortex
subcortical nucleus	all the nuclei beneath the cerebral cortex, including the basal nuclei and the basal forebrain
substantia nigra pars compacta	nuclei within the basal nuclei that release dopamine to modulate the function of the striatum; part of the motor pathway
substantia nigra pars reticulata	nuclei within the basal nuclei that serve as an output center of the nuclei; part of the motor pathway
subthalamus	nucleus within the basal nuclei that is part of the indirect pathway
sulcus	groove formed by convolutions in the surface of the cerebral cortex
superior cerebellar peduncle (SCP)	white-matter tract representing output of the cerebellum to the red nucleus of the midbrain
superior colliculus	half of the midbrain tectum that is responsible for aligning visual, auditory, and somatosensory spatial perceptions
tectum	region of the midbrain, thought of as the roof of the cerebral aqueduct, which is subdivided into the inferior and superior colliculi
tegmentum	region of the midbrain, thought of as the floor of the cerebral aqueduct, which continues into the pons and medulla as the floor of the fourth ventricle
temporal lobe	region of the cerebral cortex directly beneath the temporal bone of the cranium
vermis	prominent ridge along the midline of the cerebellum that is referred to as the spinocerebellum
thalamus	major region of the diencephalon that is responsible for relaying information between the cerebrum and the hindbrain, spinal cord, and periphery
alar plate	developmental region of the spinal cord that gives rise to the posterior horn of the gray matter
anterior column	white matter between the anterior horns of the spinal cord composed of many different groups of axons of both ascending and descending tracts
anterior horn	gray matter of the spinal cord containing multipolar motor neurons, sometimes referred to as the ventral horn
anterior median fissure	deep midline feature of the anterior spinal cord, marking the separation between the right and left sides of the cord
ascending tract	central nervous system fibers carrying sensory information from the spinal cord or periphery to the brain
basal plate	developmental region of the spinal cord that gives rise to the lateral and anterior horns of gray matter
cauda equina	bundle of spinal nerve roots that descend from the lower spinal cord below the first lumbar vertebra and lie within the vertebral cavity; has the appearance of a horse's tail
descending tract	central nervous system fibers carrying motor commands from the brain to the spinal cord or periphery
dorsal (posterior) nerve root	axons entering the posterior horn of the spinal cord
lateral column	white matter of the spinal cord between the posterior horn on one side and the axons from the anterior horn on the same side; composed of many different groups of axons, of both ascending and descending tracts, carrying motor commands to and from the brain
lateral horn	region of the spinal cord gray matter in the thoracic, upper lumbar, and sacral regions that is the central component of the sympathetic division of the autonomic nervous system
posterior columns	white matter of the spinal cord that lies between the posterior horns of the gray matter, sometimes referred to as the dorsal column; composed of axons of ascending tracts that carry sensory information up to the brain
posterior horn	gray matter region of the spinal cord in which sensory input arrives, sometimes referred to as the dorsal horn
posterior median sulcus	midline feature of the posterior spinal cord, marking the separation between right and left sides of the cord
posterolateral sulcus	feature of the posterior spinal cord marking the entry of posterior nerve roots and the separation between the posterior and lateral columns of the white matter
ventral (anterior) nerve root	axons emerging from the anterior or lateral horns of the spinal cord
abducens nerve	sixth cranial nerve; responsible for contraction of one of the extraocular muscles
axillary nerve	systemic nerve of the arm that arises from the brachial plexus
brachial plexus	nerve plexus associated with the lower cervical spinal nerves and first thoracic spinal nerve
cervical plexus	nerve plexus associated with the upper cervical spinal nerves
cranial nerve	one of twelve nerves connected to the brain that are responsible for sensory or motor functions of the head and neck
cranial nerve ganglion	sensory ganglion of cranial nerves
dorsal (posterior) root ganglion	sensory ganglion attached to the posterior nerve root of a spinal nerve
endoneurium	innermost layer of connective tissue that surrounds individual axons within a nerve
enteric nervous system	peripheral structures, namely ganglia and nerves, that are incorporated into the digestive system organs
enteric plexus	neuronal plexus in the wall of the intestines, which is part of the enteric nervous system
epineurium	outermost layer of connective tissue that surrounds an entire nerve
esophageal plexus	neuronal plexus in the wall of the esophagus that is part of the enteric nervous system
extraocular muscles	six skeletal muscles that control eye movement within the orbit
facial nerve	seventh cranial nerve; responsible for contraction of the facial muscles and for part of the sense of taste, as well as causing saliva production
fascicle	small bundles of nerve or muscle fibers enclosed by connective tissue
femoral nerve	systemic nerve of the anterior leg that arises from the lumbar plexus
fibular nerve	systemic nerve of the posterior leg that begins as part of the sciatic nerve
gastric plexuses	neuronal networks in the wall of the stomach that are part of the enteric nervous system
glossopharyngeal nerve	ninth cranial nerve; responsible for contraction of muscles in the tongue and throat and for part of the sense of taste, as well as causing saliva production
hypoglossal nerve	twelfth cranial nerve; responsible for contraction of muscles of the tongue
intercostal nerve	systemic nerve in the thoracic cavity that is found between two ribs
lumbar plexus	nerve plexus associated with the lumbar spinal nerves
median nerve	systemic nerve of the arm, located between the ulnar and radial nerves
nerve plexus	network of nerves without neuronal cell bodies included
oculomotor nerve	third cranial nerve; responsible for contraction of four of the extraocular muscles, the muscle in the upper eyelid, and pupillary constriction
olfactory nerve	first cranial nerve; responsible for the sense of smell
optic nerve	second cranial nerve; responsible for visual sensation
paravertebral ganglia	autonomic ganglia superior to the sympathetic chain ganglia
perineurium	layer of connective tissue surrounding fascicles within a nerve
phrenic nerve	systemic nerve from the cervical plexus that enervates the diaphragm
plexus	network of nerves or nervous tissue
prevertebral ganglia	autonomic ganglia that are anterior to the vertebral column and functionally related to the sympathetic chain ganglia
radial nerve	systemic nerve of the arm, the distal component of which is located near the radial bone
sacral plexus	nerve plexus associated with the lower lumbar and sacral spinal nerves
saphenous nerve	systemic nerve of the lower anterior leg that is a branch from the femoral nerve
sciatic nerve	systemic nerve from the sacral plexus that is a combination of the tibial and fibular nerves and extends across the hip joint and gluteal region into the upper posterior leg
sciatica	painful condition resulting from inflammation or compression of the sciatic nerve or any of the spinal nerves that contribute to it
spinal accessory nerve	eleventh cranial nerve; responsible for contraction of neck muscles
spinal nerve	one of 31 nerves connected to the spinal cord
sympathetic chain ganglia	autonomic ganglia in a chain along the anterolateral aspect of the vertebral column that are responsible for contributing to homeostatic mechanisms of the autonomic nervous system
systemic nerve	nerve in the periphery distal to a nerve plexus or spinal nerve
terminal ganglion	autonomic ganglia that are near or within the walls of organs that are responsible for contributing to homeostatic mechanisms of the autonomic nervous system
tibial nerve	systemic nerve of the posterior leg that begins as part of the sciatic nerve
trigeminal ganglion	sensory ganglion that contributes sensory fibers to the trigeminal nerve
trigeminal nerve	fifth cranial nerve; responsible for cutaneous sensation of the face and contraction of the muscles of mastication
trochlear nerve	fourth cranial nerve; responsible for contraction of one of the extraocular muscles
ulnar nerve	systemic nerve of the arm located close to the ulna, a bone of the forearm
vagus nerve	tenth cranial nerve; responsible for the autonomic control of organs in the thoracic and upper abdominal cavities
vestibulocochlear nerve	eighth cranial nerve; responsible for the sensations of hearing and balance
alkaloid	substance, usually from a plant source, that is chemically basic with respect to pH and will stimulate bitter receptors
amacrine cell	type of cell in the retina that connects to the bipolar cells near the outer synaptic layer and provides the basis for early image processing within the retina
ampulla	in the ear, the structure at the base of a semicircular canal that contains the hair cells and cupula for transduction of rotational movement of the head
anosmia	loss of the sense of smell; usually the result of physical disruption of the first cranial nerve
aqueous humor	watery fluid that fills the anterior chamber containing the cornea, iris, ciliary body, and lens of the eye
audition	sense of hearing
auricle	fleshy external structure of the ear
basilar membrane	in the ear, the floor of the cochlear duct on which the organ of Corti sits
bipolar cell	cell type in the retina that connects the photoreceptors to the RGCs
capsaicin	molecule that activates nociceptors by interacting with a temperature-sensitive ion channel and is the basis for “hot” sensations in spicy food
chemoreceptor	sensory receptor cell that is sensitive to chemical stimuli, such as in taste, smell, or pain
choroid	highly vascular tissue in the wall of the eye that supplies the outer retina with blood
ciliary body	smooth muscle structure on the interior surface of the iris that controls the shape of the lens through the zonule fibers
cochlea	auditory portion of the inner ear containing structures to transduce sound stimuli
cochlear duct	space within the auditory portion of the inner ear that contains the organ of Corti and is adjacent to the scala tympani and scala vestibuli on either side
cone photoreceptor	one of the two types of retinal receptor cell that is specialized for color vision through the use of three photopigments distributed through three separate populations of cells
contralateral	word meaning “on the opposite side,” as in axons that cross the midline in a fiber tract
cornea	fibrous covering of the anterior region of the eye that is transparent so that light can pass through it
cupula	specialized structure within the base of a semicircular canal that bends the stereocilia of hair cells when the head rotates by way of the relative movement of the enclosed fluid
encapsulated ending	configuration of a sensory receptor neuron with dendrites surrounded by specialized structures to aid in transduction of a particular type of sensation, such as the lamellated corpuscles in the deep dermis and subcutaneous tissue
equilibrium	sense of balance that includes sensations of position and movement of the head
external ear	structures on the lateral surface of the head, including the auricle and the ear canal back to the tympanic membrane
exteroceptor	sensory receptor that is positioned to interpret stimuli from the external environment, such as photoreceptors in the eye or somatosensory receptors in the skin
extraocular muscle	one of six muscles originating out of the bones of the orbit and inserting into the surface of the eye which are responsible for moving the eye
fibrous tunic	outer layer of the eye primarily composed of connective tissue known as the sclera and cornea
fovea	exact center of the retina at which visual stimuli are focused for maximal acuity, where the retina is thinnest, at which there is nothing but photoreceptors
free nerve ending	configuration of a sensory receptor neuron with dendrites in the connective tissue of the organ, such as in the dermis of the skin, that are most often sensitive to chemical, thermal, and mechanical stimuli
general sense	any sensory system that is distributed throughout the body and incorporated into organs of multiple other systems, such as the walls of the digestive organs or the skin
gustation	sense of taste
gustatory receptor cells	sensory cells in the taste bud that transduce the chemical stimuli of gustation
hair cells	mechanoreceptor cells found in the inner ear that transduce stimuli for the senses of hearing and balance
vertebral arteries	arteries that ascend along either side of the vertebral column through the transverse foramina of the cervical vertebrae and enter the cranium through the foramen magnum
incus	(also, anvil) ossicle of the middle ear that connects the malleus to the stapes
inferior oblique	extraocular muscle responsible for lateral rotation of the eye
inferior rectus	extraocular muscle responsible for looking down
inner ear	structure within the temporal bone that contains the sensory apparati of hearing and balance
inner segment	in the eye, the section of a photoreceptor that contains the nucleus and other major organelles for normal cellular functions
inner synaptic layer	layer in the retina where bipolar cells connect to RGCs
interoceptor	sensory receptor that is positioned to interpret stimuli from internal organs, such as stretch receptors in the wall of blood vessels
ipsilateral	word meaning on the same side, as in axons that do not cross the midline in a fiber tract
iris	colored portion of the anterior eye that surrounds the pupil
kinesthesia	sense of body movement based on sensations in skeletal muscles, tendons, joints, and the skin
lacrimal duct	duct in the medial corner of the orbit that drains tears into the nasal cavity
lacrimal gland	gland lateral to the orbit that produces tears to wash across the surface of the eye
lateral rectus	extraocular muscle responsible for abduction of the eye
lens	component of the eye that focuses light on the retina
levator palpebrae superioris	muscle that causes elevation of the upper eyelid, controlled by fibers in the oculomotor nerve
macula	enlargement at the base of a semicircular canal at which transduction of equilibrium stimuli takes place within the ampulla
malleus	(also, hammer) ossicle that is directly attached to the tympanic membrane
mechanoreceptor	receptor cell that transduces mechanical stimuli into an electrochemical signal
medial rectus	extraocular muscle responsible for adduction of the eye
middle ear	space within the temporal bone between the ear canal and bony labyrinth where the ossicles amplify sound waves from the tympanic membrane to the oval window
neural tunic	layer of the eye that contains nervous tissue, namely the retina
nociceptor	receptor cell that senses pain stimuli
odorant molecules	volatile chemicals that bind to receptor proteins in olfactory neurons to stimulate the sense of smell
olfaction	sense of smell
olfactory bulb	central target of the first cranial nerve; located on the ventral surface of the frontal lobe in the cerebrum
olfactory epithelium	region of the nasal epithelium where olfactory neurons are located
olfactory sensory neuron	receptor cell of the olfactory system, sensitive to the chemical stimuli of smell, the axons of which compose the first cranial nerve
opsin	protein that contains the photosensitive cofactor retinal for phototransduction
optic disc	spot on the retina at which RGC axons leave the eye and blood vessels of the inner retina pass
optic nerve	second cranial nerve, which is responsible visual sensation
organ of Corti	structure in the cochlea in which hair cells transduce movements from sound waves into electrochemical signals
osmoreceptor	receptor cell that senses differences in the concentrations of bodily fluids on the basis of osmotic pressure
ossicles	three small bones in the middle ear
otolith	layer of calcium carbonate crystals located on top of the otolithic membrane
otolithic membrane	gelatinous substance in the utricle and saccule of the inner ear that contains calcium carbonate crystals and into which the stereocilia of hair cells are embedded
outer segment	in the eye, the section of a photoreceptor that contains opsin molecules that transduce light stimuli
outer synaptic layer	layer in the retina at which photoreceptors connect to bipolar cells
oval window	membrane at the base of the cochlea where the stapes attaches, marking the beginning of the scala vestibuli
palpebral conjunctiva	membrane attached to the inner surface of the eyelids that covers the anterior surface of the cornea
papilla	for gustation, a bump-like projection on the surface of the tongue that contains taste buds
photoisomerization	chemical change in the retinal molecule that alters the bonding so that it switches from the 11-cis-retinal isomer to the all-trans-retinal isomer
photon	individual “packet” of light
photoreceptor	receptor cell specialized to respond to light stimuli
proprioception	sense of position and movement of the body
proprioceptor	receptor cell that senses changes in the position and kinesthetic aspects of the body
pupil	open hole at the center of the iris that light passes through into the eye
receptor cell	cell that transduces environmental stimuli into neural signals
retina	nervous tissue of the eye at which phototransduction takes place
retinal	cofactor in an opsin molecule that undergoes a biochemical change when struck by a photon (pronounced with a stress on the last syllable)
retinal ganglion cell (RGC)	neuron of the retina that projects along the second cranial nerve
rhodopsin	photopigment molecule found in the rod photoreceptors
rod photoreceptor	one of the two types of retinal receptor cell that is specialized for low-light vision
round window	membrane that marks the end of the scala tympani
saccule	structure of the inner ear responsible for transducing linear acceleration in the vertical plane
scala tympani	portion of the cochlea that extends from the apex to the round window
scala vestibuli	portion of the cochlea that extends from the oval window to the apex
sclera	white of the eye
semicircular canals	structures within the inner ear responsible for transducing rotational movement information
sensory modality	a particular system for interpreting and perceiving environmental stimuli by the nervous system
somatosensation	general sense associated with modalities lumped together as touch
special sense	any sensory system associated with a specific organ structure, namely smell, taste, sight, hearing, and balance
spiral ganglion	location of neuronal cell bodies that transmit auditory information along the eighth cranial nerve
stapes	(also, stirrup) ossicle of the middle ear that is attached to the inner ear
stereocilia	array of apical membrane extensions in a hair cell that transduce movements when they are bent
submodality	specific sense within a broader major sense such as sweet as a part of the sense of taste, or color as a part of vision
superior oblique	extraocular muscle responsible for medial rotation of the eye
superior rectus	extraocular muscle responsible for looking up
taste buds	structures within a papilla on the tongue that contain gustatory receptor cells
tectorial membrane	component of the organ of Corti that lays over the hair cells, into which the stereocilia are embedded
thermoreceptor	sensory receptor specialized for temperature stimuli
topographical	relating to positional information
transduction	process of changing an environmental stimulus into the electrochemical signals of the nervous system
trochlea	cartilaginous structure that acts like a pulley for the superior oblique muscle
tympanic membrane	ear drum
umami	taste submodality for sensitivity to the concentration of amino acids; also called the savory sense
utricle	structure of the inner ear responsible for transducing linear acceleration in the horizontal plane
vascular tunic	middle layer of the eye primarily composed of connective tissue with a rich blood supply
vestibular ganglion	location of neuronal cell bodies that transmit equilibrium information along the eighth cranial nerve
vestibule	in the ear, the portion of the inner ear responsible for the sense of equilibrium
visceral sense	sense associated with the internal organs
vision	special sense of sight based on transduction of light stimuli
visual acuity	property of vision related to the sharpness of focus, which varies in relation to retinal position
vitreous humor	viscous fluid that fills the posterior chamber of the eye
zonule fibers	fibrous connections between the ciliary body and the lens
ascending pathway	fiber structure that relays sensory information from the periphery through the spinal cord and brain stem to other structures of the brain
association area	region of cortex connected to a primary sensory cortical area that further processes the information to generate more complex sensory perceptions
binocular depth cues	indications of the distance of visual stimuli on the basis of slight differences in the images projected onto either retina
chief sensory nucleus	component of the trigeminal nuclei that is found in the pons
circadian rhythm	internal perception of the daily cycle of light and dark based on retinal activity related to sunlight
decussate	to cross the midline, as in fibers that project from one side of the body to the other
dorsal column system	ascending tract of the spinal cord associated with fine touch and proprioceptive sensations
dorsal stream	connections between cortical areas from the occipital to parietal lobes that are responsible for the perception of visual motion and guiding movement of the body in relation to that motion
fasciculus cuneatus	lateral division of the dorsal column system composed of fibers from sensory neurons in the upper body
fasciculus gracilis	medial division of the dorsal column system composed of fibers from sensory neurons in the lower body
inferior colliculus	last structure in the auditory brainstem pathway that projects to the thalamus and superior colliculus
interaural intensity difference	cue used to aid sound localization in the horizontal plane that compares the relative loudness of sounds at the two ears, because the ear closer to the sound source will hear a slightly more intense sound
interaural time difference	cue used to help with sound localization in the horizontal plane that compares the relative time of arrival of sounds at the two ears, because the ear closer to the sound source will receive the stimulus microseconds before the other ear
lateral geniculate nucleus	thalamic target of the RGCs that projects to the visual cortex
medial geniculate nucleus	thalamic target of the auditory brain stem that projects to the auditory cortex
medial lemniscus	fiber tract of the dorsal column system that extends from the nuclei gracilis and cuneatus to the thalamus, and decussates
mesencephalic nucleus	component of the trigeminal nuclei that is found in the midbrain
multimodal integration area	region of the cerebral cortex in which information from more than one sensory modality is processed to arrive at higher level cortical functions such as memory, learning, or cognition
nucleus cuneatus	medullary nucleus at which first-order neurons of the dorsal column system synapse specifically from the upper body and arms
nucleus gracilis	medullary nucleus at which first-order neurons of the dorsal column system synapse specifically from the lower body and legs
optic chiasm	decussation point in the visual system at which medial retina fibers cross to the other side of the brain
optic tract	name for the fiber structure containing axons from the retina posterior to the optic chiasm representing their CNS location
primary sensory cortex	region of the cerebral cortex that initially receives sensory input from an ascending pathway from the thalamus and begins the processing that will result in conscious perception of that modality
sensory homunculus	topographic representation of the body within the somatosensory cortex demonstrating the correspondence between neurons processing stimuli and sensitivity
solitary nucleus	medullar nucleus that receives taste information from the facial and glossopharyngeal nerves
spinal trigeminal nucleus	component of the trigeminal nuclei that is found in the medulla
spinothalamic tract	ascending tract of the spinal cord associated with pain and temperature sensations
superior colliculus	structure in the midbrain that combines visual, auditory, and somatosensory input to coordinate spatial and topographic representations of the three sensory systems
suprachiasmatic nucleus	hypothalamic target of the retina that helps to establish the circadian rhythm of the body on the basis of the presence or absence of daylight
ventral posterior nucleus	nucleus in the thalamus that is the target of gustatory sensations and projects to the cerebral cortex
ventral stream	connections between cortical areas from the occipital lobe to the temporal lobe that are responsible for identification of visual stimuli
vestibular nuclei	targets of the vestibular component of the eighth cranial nerve
vestibulo-ocular reflex (VOR)	reflex based on connections between the vestibular system and the cranial nerves of eye movements that ensures images are stabilized on the retina as the head and body move
anterior corticospinal tract	division of the corticospinal pathway that travels through the ventral (anterior) column of the spinal cord and controls axial musculature through the medial motor neurons in the ventral (anterior) horn
Betz cells	output cells of the primary motor cortex that cause musculature to move through synapses on cranial and spinal motor neurons
Broca’s area	region of the frontal lobe associated with the motor commands necessary for speech production
cerebral peduncles	segments of the descending motor pathway that make up the white matter of the ventral midbrain
cervical enlargement	region of the ventral (anterior) horn of the spinal cord that has a larger population of motor neurons for the greater number of and finer control of muscles of the upper limb
corneal reflex	protective response to stimulation of the cornea causing contraction of the orbicularis oculi muscle resulting in blinking of the eye
corticobulbar tract	connection between the cortex and the brain stem responsible for generating movement
corticospinal tract	connection between the cortex and the spinal cord responsible for generating movement
executive functions	cognitive processes of the prefrontal cortex that lead to directing goal-directed behavior, which is a precursor to executing motor commands
extrapyramidal system	pathways between the brain and spinal cord that are separate from the corticospinal tract and are responsible for modulating the movements generated through that primary pathway
frontal eye fields	area of the prefrontal cortex responsible for moving the eyes to attend to visual stimuli
internal capsule	segment of the descending motor pathway that passes between the caudate nucleus and the putamen
lateral corticospinal tract	division of the corticospinal pathway that travels through the lateral column of the spinal cord and controls appendicular musculature through the lateral motor neurons in the ventral (anterior) horn
lumbar enlargement	region of the ventral (anterior) horn of the spinal cord that has a larger population of motor neurons for the greater number of muscles of the lower limb
premotor cortex	cortical area anterior to the primary motor cortex that is responsible for planning movements
pyramidal decussation	location at which corticospinal tract fibers cross the midline and segregate into the anterior and lateral divisions of the pathway
pyramids	segment of the descending motor pathway that travels in the anterior position of the medulla
red nucleus	midbrain nucleus that sends corrective commands to the spinal cord along the rubrospinal tract, based on disparity between an original command and the sensory feedback from movement
reticulospinal tract	extrapyramidal connections between the brain stem and spinal cord that modulate movement, contribute to posture, and regulate muscle tone
rubrospinal tract	descending motor control pathway, originating in the red nucleus, that mediates control of the limbs on the basis of cerebellar processing
stretch reflex	response to activation of the muscle spindle stretch receptor that causes contraction of the muscle to maintain a constant length
supplemental motor area	cortical area anterior to the primary motor cortex that is responsible for planning movements
tectospinal tract	extrapyramidal connections between the superior colliculus and spinal cord
vestibulospinal tract	extrapyramidal connections between the vestibular nuclei in the brain stem and spinal cord that modulate movement and contribute to balance on the basis of the sense of equilibrium
working memory	function of the prefrontal cortex to maintain a representation of information that is not in the immediate environment
alpha (α)-adrenergic receptor	one of the receptors to which epinephrine and norepinephrine bind, which comes in three subtypes: α₁, α₂, and α₃
acetylcholine (ACh)	neurotransmitter that binds at a motor end-plate to trigger depolarization
adrenal medulla	interior portion of the adrenal (or suprarenal) gland that releases epinephrine and norepinephrine into the bloodstream as hormones
adrenergic	synapse where norepinephrine is released, which binds to α- or β-adrenergic receptors
beta (β)-adrenergic receptor	one of the receptors to which epinephrine and norepinephrine bind, which comes in two subtypes: β₁ and β₂
celiac ganglion	one of the collateral ganglia of the sympathetic system that projects to the digestive system
central neuron	specifically referring to the cell body of a neuron in the autonomic system that is located in the central nervous system, specifically the lateral horn of the spinal cord or a brain stem nucleus
cholinergic	synapse at which acetylcholine is released and binds to the nicotinic or muscarinic receptor
chromaffin cells	neuroendocrine cells of the adrenal medulla that release epinephrine and norepinephrine into the bloodstream as part of sympathetic system activity
ciliary ganglion	one of the terminal ganglia of the parasympathetic system, located in the posterior orbit, axons from which project to the iris
collateral ganglia	ganglia outside of the sympathetic chain that are targets of sympathetic preganglionic fibers, which are the celiac, inferior mesenteric, and superior mesenteric ganglia
craniosacral system	alternate name for the parasympathetic division of the autonomic nervous system that is based on the anatomical location of central neurons in brain-stem nuclei and the lateral horn of the sacral spinal cord; also referred to as craniosacral outflow
dorsal nucleus of the vagus nerve	location of parasympathetic neurons that project through the vagus nerve to terminal ganglia in the thoracic and abdominal cavities
Eddinger–Westphal nucleus	location of parasympathetic neurons that project to the ciliary ganglion
endogenous	describes substance made in the human body
epinephrine	signaling molecule released from the adrenal medulla into the bloodstream as part of the sympathetic response
exogenous	describes substance made outside of the human body
fight-or-flight response	set of responses induced by sympathetic activity that lead to either fleeing a threat or standing up to it, which in the modern world is often associated with anxious feelings
G protein–coupled receptor	membrane protein complex that consists of a receptor protein that binds to a signaling molecule—a G protein—that is activated by that binding and in turn activates an effector protein (enzyme) that creates a second-messenger molecule in the cytoplasm of the target cell
ganglionic neuron	specifically refers to the cell body of a neuron in the autonomic system that is located in a ganglion
gray rami communicantes	(singular = ramus communicans) unmyelinated structures that provide a short connection from a sympathetic chain ganglion to the spinal nerve that contains the postganglionic sympathetic fiber
greater splanchnic nerve	nerve that contains fibers of the central sympathetic neurons that do not synapse in the chain ganglia but project onto the celiac ganglion
inferior mesenteric ganglion	one of the collateral ganglia of the sympathetic system that projects to the digestive system
intramural ganglia	terminal ganglia of the parasympathetic system that are found within the walls of the target effector
lesser splanchnic nerve	nerve that contains fibers of the central sympathetic neurons that do not synapse in the chain ganglia but project onto the inferior mesenteric ganglion
ligand-gated cation channel	ion channel, such as the nicotinic receptor, that is specific to positively charged ions and opens when a molecule such as a neurotransmitter binds to it
mesenteric plexus	nervous tissue within the wall of the digestive tract that contains neurons that are the targets of autonomic preganglionic fibers and that project to the smooth muscle and glandular tissues in the digestive organ
muscarinic receptor	type of acetylcholine receptor protein that is characterized by also binding to muscarine and is a metabotropic receptor
nicotinic receptor	type of acetylcholine receptor protein that is characterized by also binding to nicotine and is an ionotropic receptor
norepinephrine	signaling molecule released as a neurotransmitter by most postganglionic sympathetic fibers as part of the sympathetic response, or as a hormone into the bloodstream from the adrenal medulla
nucleus ambiguus	brain-stem nucleus that contains neurons that project through the vagus nerve to terminal ganglia in the thoracic cavity; specifically associated with the heart
parasympathetic division	division of the autonomic nervous system responsible for restful and digestive functions
paravertebral ganglia	autonomic ganglia superior to the sympathetic chain ganglia
postganglionic fiber	axon from a ganglionic neuron in the autonomic nervous system that projects to and synapses with the target effector; sometimes referred to as a postganglionic neuron
preganglionic fiber	axon from a central neuron in the autonomic nervous system that projects to and synapses with a ganglionic neuron; sometimes referred to as a preganglionic neuron
prevertebral ganglia	autonomic ganglia that are anterior to the vertebral column and functionally related to the sympathetic chain ganglia
rest and digest	set of functions associated with the parasympathetic system that lead to restful actions and digestion
superior cervical ganglion	one of the paravertebral ganglia of the sympathetic system that projects to the head
superior mesenteric ganglion	one of the collateral ganglia of the sympathetic system that projects to the digestive system
sympathetic chain ganglia	series of ganglia adjacent to the vertebral column that receive input from central sympathetic neurons
sympathetic division	division of the autonomic nervous system associated with the fight-or-flight response
target effector	organ, tissue, or gland that will respond to the control of an autonomic or somatic or endocrine signal
terminal ganglia	ganglia of the parasympathetic division of the autonomic system, which are located near or within the target effector, the latter also known as intramural ganglia
thoracolumbar system	alternate name for the sympathetic division of the autonomic nervous system that is based on the anatomical location of central neurons in the lateral horn of the thoracic and upper lumbar spinal cord
varicosity	structure of some autonomic connections that is not a typical synaptic end bulb, but a string of swellings along the length of a fiber that makes a network of connections with the target effector
white rami communicantes	(singular = ramus communicans) myelinated structures that provide a short connection from a sympathetic chain ganglion to the spinal nerve that contains the preganglionic sympathetic fiber
autonomic tone	tendency of an organ system to be governed by one division of the autonomic nervous system over the other, such as heart rate being lowered by parasympathetic input at rest
afferent branch	component of a reflex arc that represents the input from a sensory neuron, for either a special or general sense
baroreceptor	mechanoreceptor that senses the stretch of blood vessels to indicate changes in blood pressure
efferent branch	component of a reflex arc that represents the output, with the target being an effector, such as muscle or glandular tissue
long reflex	reflex arc that includes the central nervous system
referred pain	the conscious perception of visceral sensation projected to a different region of the body, such as the left shoulder and arm pain as a sign for a heart attack
reflex arc	circuit of a reflex that involves a sensory input and motor output, or an afferent branch and an efferent branch, and an integrating center to connect the two branches
short reflex	reflex arc that does not include any components of the central nervous system
somatic reflex	reflex involving skeletal muscle as the effector, under the control of the somatic nervous system
visceral reflex	reflex involving an internal organ as the effector, under the control of the autonomic nervous system
cardiac accelerator nerves	preganglionic sympathetic fibers that cause the heart rate to increase when the cardiovascular center in the medulla initiates a signal
cardiovascular center	region in the medulla that controls the cardiovascular system through cardiac accelerator nerves and vasomotor nerves, which are components of the sympathetic division of the autonomic nervous system
dorsal longitudinal fasciculus	major output pathway of the hypothalamus that descends through the gray matter of the brain stem and into the spinal cord
limbic lobe	structures arranged around the edges of the cerebrum that are involved in memory and emotion
medial forebrain bundle	fiber pathway that extends anteriorly into the basal forebrain, passes through the hypothalamus, and extends into the brain stem and spinal cord
vasomotor nerves	preganglionic sympathetic fibers that cause the constriction of blood vessels in response to signals from the cardiovascular center
autocrine	chemical signal that elicits a response in the same cell that secreted it
endocrine gland	tissue or organ that secretes hormones into the blood and lymph without ducts such that they may be transported to organs distant from the site of secretion
endocrine system	cells, tissues, and organs that secrete hormones as a primary or secondary function and play an integral role in normal bodily processes
exocrine system	cells, tissues, and organs that secrete substances directly to target tissues via glandular ducts
hormone receptor	protein within a cell or on the cell membrane that binds a hormone, initiating the target cell response
hormone	secretion of an endocrine organ that travels via the bloodstream or lymphatics to induce a response in target cells or tissues in another part of the body
humoral stimuli	changes in blood levels of non-hormone chemicals such as ions or nutrients that cause release or inhibition of a hormone to maintain homeostasis of the chemical
negative feedback loop	type of regulation in which increasing levels of a substance signal that the substance no longer needs to be released, resulting in lowered levels of the substance
paracrine	chemical signal that elicits a response in neighboring cells; also called paracrine factor
adrenocorticotropic hormone (ACTH)	anterior pituitary hormone that stimulates the adrenal cortex to secrete corticosteroid hormones (also called corticotropin)
antidiuretic hormone (ADH)	hypothalamic hormone that is stored by the posterior pituitary and that signals the kidneys to reabsorb water
follicle-stimulating hormone (FSH)	anterior pituitary hormone that stimulates the production and maturation of sex cells
gonadotropins	hormones that regulate the function of the gonads
growth hormone (GH)	anterior pituitary hormone that promotes tissue building and influences nutrient metabolism (also called somatotropin)
hypophyseal portal system	network of blood vessels that enables hypothalamic hormones to travel into the anterior lobe of the pituitary without entering the systemic circulation
hypothalamus	region of the diencephalon inferior to the thalamus that functions in neural and endocrine signaling
infundibulum	stalk containing vasculature and neural tissue that connects the pituitary gland to the hypothalamus (also called the pituitary stalk)
insulin-like growth factors (IGF)	protein that enhances cellular proliferation, inhibits apoptosis, and stimulates the cellular uptake of amino acids for protein synthesis
luteinizing hormone (LH)	anterior pituitary hormone that triggers ovulation and the production of ovarian hormones in females, and the production of testosterone in males
osmoreceptor	hypothalamic sensory receptor that is stimulated by changes in solute concentration (osmotic pressure) in the blood
oxytocin	hypothalamic hormone stored in the posterior pituitary gland and important in stimulating uterine contractions in labor, milk ejection during breastfeeding, and feelings of attachment (also produced in males)
pituitary gland	bean-sized organ suspended from the hypothalamus that produces, stores, and secretes hormones in response to hypothalamic stimulation (also called hypophysis)
prolactin (PRL)	anterior pituitary hormone that promotes development of the mammary glands and the production of breast milk
thyroid-stimulating hormone (TSH)	anterior pituitary hormone that triggers secretion of thyroid hormones by the thyroid gland (also called thyrotropin)
calcitonin	peptide hormone produced and secreted by the parafollicular cells (C cells) of the thyroid gland that functions to decrease blood calcium levels
colloid	viscous fluid in the central cavity of thyroid follicles, containing the glycoprotein thyroglobulin
goiter	enlargement of the thyroid gland either as a result of iodine deficiency or hyperthyroidism
hyperthyroidism	clinically abnormal, elevated level of thyroid hormone in the blood; characterized by an increased metabolic rate, excess body heat, sweating, diarrhea, weight loss, and increased heart rate
hypothyroidism	clinically abnormal, low level of thyroid hormone in the blood; characterized by low metabolic rate, weight gain, cold extremities, constipation, and reduced mental activity
neonatal hypothyroidism	condition characterized by cognitive deficits, short stature, and other signs and symptoms in people born to women who were iodine-deficient during pregnancy
thyroid gland	large endocrine gland responsible for the synthesis of thyroid hormones
thyroxine	(also, tetraiodothyronine, T₄) amino acid–derived thyroid hormone that is more abundant but less potent than T₃and often converted to T₃ by target cells
triiodothyronine	(also, T₃) amino acid–derived thyroid hormone that is less abundant but more potent than T₄
hyperparathyroidism	disorder caused by overproduction of PTH that results in abnormally elevated blood calcium
hypoparathyroidism	disorder caused by underproduction of PTH that results in abnormally low blood calcium
parathyroid glands	small, round glands embedded in the posterior thyroid gland that produce parathyroid hormone (PTH)
parathyroid hormone (PTH)	peptide hormone produced and secreted by the parathyroid glands in response to low blood calcium levels
adrenal cortex	outer region of the adrenal glands consisting of multiple layers of epithelial cells and capillary networks that produces mineralocorticoids and glucocorticoids
adrenal glands	endocrine glands located at the top of each kidney that are important for the regulation of the stress response, blood pressure and blood volume, water homeostasis, and electrolyte levels
adrenal medulla	inner layer of the adrenal glands that plays an important role in the stress response by producing epinephrine and norepinephrine
angiotensin-converting enzyme	the enzyme that converts angiotensin I to angiotensin II
alarm reaction	the short-term stress, or the fight-or-flight response, of stage one of the general adaptation syndrome mediated by the hormones epinephrine and norepinephrine
aldosterone	hormone produced and secreted by the adrenal cortex that stimulates sodium and fluid retention and increases blood volume and blood pressure
chromaffin	neuroendocrine cells of the adrenal medulla
cortisol	glucocorticoid important in gluconeogenesis, the catabolism of glycogen, and downregulation of the immune system
epinephrine	primary and most potent catecholamine hormone secreted by the adrenal medulla in response to short-term stress; also called adrenaline
general adaptation syndrome (GAS)	the human body’s three-stage response pattern to short- and long-term stress
glucocorticoids	hormones produced by the zona fasciculata of the adrenal cortex that influence glucose metabolism
mineralocorticoids	hormones produced by the zona glomerulosa cells of the adrenal cortex that influence fluid and electrolyte balance
norepinephrine	secondary catecholamine hormone secreted by the adrenal medulla in response to short-term stress; also called noradrenaline
stage of exhaustion	stage three of the general adaptation syndrome; the body’s long-term response to stress mediated by the hormones of the adrenal cortex
stage of resistance	stage two of the general adaptation syndrome; the body’s continued response to stress after stage one diminishes
zona fasciculata	intermediate region of the adrenal cortex that produce hormones called glucocorticoids
zona glomerulosa	most superficial region of the adrenal cortex, which produces the hormones collectively referred to as mineralocorticoids
zona reticularis	deepest region of the adrenal cortex, which produces the steroid sex hormones called androgens
melatonin	amino acid–derived hormone that is secreted in response to low light and causes drowsiness
pineal gland	endocrine gland that secretes melatonin, which is important in regulating the sleep-wake cycle
pinealocyte	cell of the pineal gland that produces and secretes the hormone melatonin
estrogens	class of predominantly female sex hormones important for the development and growth of the female reproductive tract, secondary sex characteristics, the female reproductive cycle, and the maintenance of pregnancy
inhibin	hormone secreted by the male and female gonads that inhibits FSH production by the anterior pituitary
progesterone	predominantly female sex hormone important in regulating the female reproductive cycle and the maintenance of pregnancy
testosterone	steroid hormone secreted by the male testes and important in the maturation of sperm cells, growth and development of the male reproductive system, and the development of male secondary sex characteristics
alpha cell	pancreatic islet cell type that produces the hormone glucagon
beta cell	pancreatic islet cell type that produces the hormone insulin
delta cell	minor cell type in the pancreas that secretes the hormone somatostatin
diabetes mellitus	condition caused by destruction or dysfunction of the beta cells of the pancreas or cellular resistance to insulin that results in abnormally high blood glucose levels
glucagon	pancreatic hormone that stimulates the catabolism of glycogen to glucose, thereby increasing blood glucose levels
hyperglycemia	abnormally high blood glucose levels
insulin	pancreatic hormone that enhances the cellular uptake and utilization of glucose, thereby decreasing blood glucose levels
pancreas	organ with both exocrine and endocrine functions located posterior to the stomach that is important for digestion and the regulation of blood glucose
pancreatic islets	specialized clusters of pancreatic cells that have endocrine functions; also called islets of Langerhans
PP cell	minor cell type in the pancreas that secretes the hormone pancreatic polypeptide
atrial natriuretic peptide (ANP)	hormone secreted by the atria of the heart to signal for a reduction in blood volume, blood pressure, and blood sodium levels
erythropoietin (EPO)	hormone secreted by the kidney to stimulate production of red blood cells in order to increase blood oxygen levels
leptin	protein hormone secreted by adipose tissues in response to food consumption that promotes satiety
albumin	most abundant plasma protein, accounting for most of the osmotic pressure of plasma
antibodies	(also, immunoglobulins or gamma globulins) antigen-specific proteins produced by specialized B lymphocytes that protect the body by binding to foreign objects such as bacteria and viruses
blood	liquid connective tissue composed of formed elements—erythrocytes, leukocytes, and platelets—and a fluid extracellular matrix called plasma; component of the cardiovascular system
buffy coat	thin, pale layer of leukocytes and platelets that separates the erythrocytes from the plasma in a sample of centrifuged blood
complete blood count (CBC) with differential	a test in which a prepared microscope slide of a patient's blood is used to count the numbers of each type of formed element visible in a given volume of blood; observations about the size, shape, and characteristics of each type of formed element are also made
fibrinogen	plasma protein produced in the liver and involved in blood clotting
formed elements	cellular components of blood; that is, erythrocytes, leukocytes, and platelets
globulins	heterogeneous group of plasma proteins that includes transport proteins, clotting factors, immune proteins, and others
hematocrit	(also, packed cell volume) volume percentage of erythrocytes in a sample of centrifuged blood
immunoglobulins	(also, antibodies or gamma globulins) antigen-specific proteins produced by specialized B lymphocytes that protect the body by binding to foreign objects such as bacteria and viruses
packed cell volume (PCV)	(also, hematocrit) volume percentage of erythrocytes present in a sample of centrifuged blood
plasma	in blood, the liquid extracellular matrix composed mostly of water that circulates the formed elements and dissolved materials throughout the cardiovascular system
platelets	(also, thrombocytes) one of the formed elements of blood that consists of cell fragments broken off from megakaryocytes
red blood cells (RBCs)	(also, erythrocytes) one of the formed elements of blood that transports oxygen
anemia	deficiency of red blood cells or hemoglobin
bilirubin	yellowish bile pigment produced when iron is removed from heme and is further broken down into waste products
biliverdin	green bile pigment produced when the non-iron portion of heme is degraded into a waste product; converted to bilirubin in the liver
carbaminohemoglobin	compound of carbon dioxide and hemoglobin, and one of the ways in which carbon dioxide is carried in the blood
deoxyhemoglobin	molecule of hemoglobin without an oxygen molecule bound to it
erythrocyte	(also, red blood cell) mature myeloid blood cell that is composed mostly of hemoglobin and functions primarily in the transportation of oxygen and carbon dioxide
globin	heme-containing globular protein that is a constituent of hemoglobin
heme	red, iron-containing pigment to which oxygen binds in hemoglobin
hemoglobin	oxygen-carrying compound in erythrocytes
hypoxemia	below-normal level of oxygen saturation of blood (typically <95 percent)
macrophage	phagocytic cell of the myeloid lineage; a matured monocyte
oxyhemoglobin	molecule of hemoglobin to which oxygen is bound
polycythemia	elevated level of hemoglobin, whether adaptive or pathological
reticulocyte	immature erythrocyte that may still contain fragments of organelles
sickle cell disease	(also, sickle cell anemia) inherited blood disorder in which hemoglobin molecules are malformed, leading to the breakdown of RBCs that take on a characteristic sickle shape
thalassemia	inherited blood disorder in which maturation of RBCs does not proceed normally, leading to abnormal formation of hemoglobin and the destruction of RBCs
agranular leukocytes	leukocytes with few granules in their cytoplasm; specifically, monocytes, lymphocytes, and NK cells
B lymphocytes	(also, B cells) lymphocytes that defend the body against specific pathogens and thereby provide specific immunity
basophils	granulocytes that stain with a basic (alkaline) stain and store histamine and heparin
blood clot	mesh of fibrin proteins and sticky platelets and red blood cells that forms a more durable and long-lasting seal for a damaged blood vessel wall during hemostasis
coagulation	process of forming a blood clot during hemostasis
defensins	antimicrobial proteins released from neutrophils and macrophages that create openings in the plasma membranes to kill cells
diapedesis	(also, emigration) process by which leukocytes squeeze through adjacent cells in a blood vessel wall to enter tissues
emigration	(also, diapedesis) process by which leukocytes squeeze through adjacent cells in a blood vessel wall to enter tissues
eosinophils	granulocytes that stain with eosin; they release antihistamines and are especially active against parasitic worms
fibrin	activated form of the plasma protein fibrinogen; elongated, fibrous protein that forms a mesh framework within a blood clot
granular leukocytes	leukocytes with abundant granules in their cytoplasm; specifically, neutrophils, eosinophils, and basophils
hemophilia	a group of genetic disorders that can result in excessive bleeding related to inadequate production of one or more clotting factors
hemostasis	stoppage of blood flow following damage to a vessel
leukemia	cancer involving leukocytes
leukocyte	(also, white blood cell) colorless, nucleated blood cell, the chief function of which is to protect the body from disease
leukocytosis	excessive leukocyte proliferation
leukopenia	below-normal production of leukocytes
lymphocytes	agranular leukocytes of the lymphoid stem cell line, many of which function in specific immunity
lymphoma	form of cancer in which masses of malignant T and/or B lymphocytes collect in lymph nodes, the spleen, the liver, and other tissues
lysozyme	digestive enzyme with bactericidal properties
megakaryocyte	bone marrow cell that produces platelets
memory cell	type of B or T lymphocyte that forms after exposure to a pathogen
monocytes	agranular leukocytes of the myeloid stem cell line that circulate in the bloodstream; tissue monocytes are macrophages
natural killer (NK) cells	cytotoxic lymphocytes capable of recognizing cells that do not express “self” proteins on their plasma membrane or that contain foreign or abnormal markers; provide generalized, nonspecific immunity
neutrophils	granulocytes that stain with a neutral dye and are the most numerous of the leukocytes; especially active against bacteria
platelet plug	temporary seal for a damaged blood vessel wall during hemostasis; comprised of sticky platelets attached to the damaged vessel wall
polymorphonuclear	having a lobed nucleus, as seen in some leukocytes
positive chemotaxis	process in which a cell is attracted to move in the direction of chemical stimuli
T lymphocytes	(also, T cells) lymphocytes that provide cellular-level immunity by physically attacking foreign or diseased cells
thrombocytes	platelets, one of the formed elements of blood that consists of cell fragments broken off from megakaryocytes
thrombocytopenia	condition in which there are too few platelets, resulting in abnormal bleeding (hemophilia)
thrombocytosis	condition in which there are too many platelets, resulting in abnormal clotting (thrombosis)
bone marrow biopsy	diagnostic test of a sample of red bone marrow
bone marrow transplant	treatment in which a donor’s healthy bone marrow with its stem cells replaces diseased or damaged bone marrow of a patient
colony-stimulating factors (CSFs)	glycoproteins that trigger the proliferation and differentiation of myeloblasts into granular leukocytes (basophils, neutrophils, and eosinophils)
cytokines	class of protein signaling molecules; in the cardiovascular system, they stimulate the proliferation of progenitor cells and help to stimulate both nonspecific and specific resistance to disease
erythropoietin (EPO)	glycoprotein that triggers the bone marrow to produce RBCs; secreted by the kidney in response to low oxygen levels
hemocytoblast	hemopoietic stem cell that gives rise to the formed elements of blood
hemopoiesis	production of the formed elements of blood
hemopoietic growth factors	chemical signals including erythropoietin, thrombopoietin, colony-stimulating factors, and interleukins that regulate the differentiation and proliferation of particular blood progenitor cells
hemopoietic stem cell	type of pluripotent stem cell that gives rise to the formed elements of blood (hemocytoblast)
interleukins	signaling molecules that may function in hemopoiesis, inflammation, and specific immune responses
lymphoid stem cells	type of hemopoietic stem cells that gives rise to lymphocytes, including various T cells, B cells, and NK cells, all of which function in immunity
myeloid stem cells	type of hemopoietic stem cell that gives rise to some formed elements, including erythrocytes, megakaryocytes that produce platelets, and a myeloblast lineage that gives rise to monocytes and three forms of granular leukocytes (neutrophils, eosinophils, and basophils)
pluripotent stem cell	stem cell that derives from totipotent stem cells and is capable of differentiating into many, but not all, cell types
totipotent stem cell	embryonic stem cell that is capable of differentiating into any and all cells of the body; enabling the full development of an organism
thrombopoietin	hormone secreted by the liver and kidneys that prompts the development of megakaryocytes into thrombocytes (platelets)
ABO blood group	blood-type classification based on the presence or absence of A and B glycoproteins on the erythrocyte membrane surface
agglutination	clustering of cells into masses linked by antibodies
cross matching	blood test for identification of blood type using antibodies and small samples of blood
hemolysis	destruction (lysis) of erythrocytes and the release of their hemoglobin into circulation
hemolytic disease of the newborn (HDN)	(also, erythroblastosis fetalis) disorder causing agglutination and hemolysis in an Rh⁺ fetus or newborn of an Rh⁻ mother
Rh blood group	blood-type classification based on the presence or absence of the antigen Rh on the erythrocyte membrane surface
universal donor	individual with type O⁻ blood
universal recipient	individual with type AB⁺ blood
anastomosis	(plural = anastomoses) area where vessels unite to allow blood to circulate even if there may be partial blockage in another branch
anterior cardiac veins	vessels that parallel the small cardiac arteries and drain the anterior surface of the right ventricle; bypass the coronary sinus and drain directly into the right atrium
anterior interventricular artery	(also, left anterior descending artery or LAD) major branch of the left coronary artery that follows the anterior interventricular sulcus
anterior interventricular sulcus	sulcus located between the left and right ventricles on the anterior surface of the heart
aortic valve	(also, aortic semilunar valve) valve located at the base of the aorta
atrioventricular septum	cardiac septum located between the atria and ventricles; atrioventricular valves are located here
atrioventricular valves	one-way valves located between the atria and ventricles; the valve on the right is called the tricuspid valve, and the one on the left is the mitral or bicuspid valve
atrium	(plural = atria) upper or receiving chamber of the heart that pumps blood into the lower chambers just prior to their contraction; the right atrium receives blood from the systemic circuit that flows into the right ventricle; the left atrium receives blood from the pulmonary circuit that flows into the left ventricle
auricle	extension of an atrium visible on the superior surface of the heart
bicuspid valve	(also, mitral valve or left atrioventricular valve) valve located between the left atrium and ventricle; consists of two flaps of tissue
cardiac notch	depression in the medial surface of the inferior lobe of the left lung where the apex of the heart is located
cardiac skeleton	(also, skeleton of the heart) reinforced connective tissue located within the atrioventricular septum; includes four rings that surround the openings between the atria and ventricles, and the openings to the pulmonary trunk and aorta; the point of attachment for the heart valves
cardiomyocyte	muscle cell of the heart
chordae tendineae	string-like extensions of tough connective tissue that extend from the flaps of the atrioventricular valves to the papillary muscles
circumflex artery	branch of the left coronary artery that follows coronary sulcus
coronary arteries	branches of the ascending aorta that supply blood to the heart; the left coronary artery feeds the left side of the heart, the left atrium and ventricle, and the interventricular septum; the right coronary artery feeds the right atrium, portions of both ventricles, and the heart conduction system
coronary sinus	large, thin-walled vein on the posterior surface of the heart that lies within the atrioventricular sulcus and drains the heart myocardium directly into the right atrium
coronary sulcus	sulcus that marks the boundary between the atria and ventricles
coronary veins	vessels that drain the heart and generally parallel the large surface arteries
endocardium	innermost layer of the heart lining the heart chambers and heart valves; composed of endothelium reinforced with a thin layer of connective tissue that binds to the myocardium
endothelium	layer of smooth, simple squamous epithelium that lines the endocardium and blood vessels
epicardial coronary arteries	surface arteries of the heart that generally follow the sulci
epicardium	innermost layer of the serous pericardium and the outermost layer of the heart wall
foramen ovale	opening in the fetal heart that allows blood to flow directly from the right atrium to the left atrium, bypassing the fetal pulmonary circuit
fossa ovalis	oval-shaped depression in the interatrial septum that marks the former location of the foramen ovale
great cardiac vein	vessel that follows the interventricular sulcus on the anterior surface of the heart and flows along the coronary sulcus into the coronary sinus on the posterior surface; parallels the anterior interventricular artery and drains the areas supplied by this vessel
hypertrophic cardiomyopathy	pathological enlargement of the heart, generally for no known reason
inferior vena cava	large systemic vein that returns blood to the heart from the inferior portion of the body
interatrial septum	cardiac septum located between the two atria; contains the fossa ovalis after birth
interventricular septum	cardiac septum located between the two ventricles
left atrioventricular valve	(also, mitral valve or bicuspid valve) valve located between the left atrium and ventricle; consists of two flaps of tissue
marginal arteries	branches of the right coronary artery that supply blood to the superficial portions of the right ventricle
mesothelium	simple squamous epithelial portion of serous membranes, such as the superficial portion of the epicardium (the visceral pericardium) and the deepest portion of the pericardium (the parietal pericardium)
middle cardiac vein	vessel that parallels and drains the areas supplied by the posterior interventricular artery; drains into the great cardiac vein
mitral valve	(also, left atrioventricular valve or bicuspid valve) valve located between the left atrium and ventricle; consists of two flaps of tissue
moderator band	band of myocardium covered by endocardium that arises from the inferior portion of the interventricular septum in the right ventricle and crosses to the anterior papillary muscle; contains conductile fibers that carry electrical signals followed by contraction of the heart
myocardium	thickest layer of the heart composed of cardiac muscle cells built upon a framework of primarily collagenous fibers and blood vessels that supply it and the nervous fibers that help to regulate it
papillary muscle	extension of the myocardium in the ventricles to which the chordae tendineae attach
pectinate muscles	muscular ridges seen on the anterior surface of the right atrium
pericardial cavity	cavity surrounding the heart filled with a lubricating serous fluid that reduces friction as the heart contracts
pericardial sac	(also, pericardium) membrane that separates the heart from other mediastinal structures; consists of two distinct, fused sublayers: the fibrous pericardium and the parietal pericardium
pericardium	(also, pericardial sac) membrane that separates the heart from other mediastinal structures; consists of two distinct, fused sublayers: the fibrous pericardium and the parietal pericardium
posterior cardiac vein	vessel that parallels and drains the areas supplied by the marginal artery branch of the circumflex artery; drains into the great cardiac vein
posterior interventricular artery	(also, posterior descending artery) branch of the right coronary artery that runs along the posterior portion of the interventricular sulcus toward the apex of the heart and gives rise to branches that supply the interventricular septum and portions of both ventricles
posterior interventricular sulcus	sulcus located between the left and right ventricles on the anterior surface of the heart
pulmonary arteries	left and right branches of the pulmonary trunk that carry deoxygenated blood from the heart to each of the lungs
pulmonary capillaries	capillaries surrounding the alveoli of the lungs where gas exchange occurs: carbon dioxide exits the blood and oxygen enters
pulmonary circuit	blood flow to and from the lungs
pulmonary trunk	large arterial vessel that carries blood ejected from the right ventricle; divides into the left and right pulmonary arteries
pulmonary valve	(also, pulmonary semilunar valve, the pulmonic valve, or the right semilunar valve) valve at the base of the pulmonary trunk that prevents backflow of blood into the right ventricle; consists of three flaps
pulmonary veins	veins that carry highly oxygenated blood into the left atrium, which pumps the blood into the left ventricle, which in turn pumps oxygenated blood into the aorta and to the many branches of the systemic circuit
right atrioventricular valve	(also, tricuspid valve) valve located between the right atrium and ventricle; consists of three flaps of tissue
semilunar valves	valves located at the base of the pulmonary trunk and at the base of the aorta
septum	(plural = septa) walls or partitions that divide the heart into chambers
septum primum	flap of tissue in the fetus that covers the foramen ovale within a few seconds after birth
small cardiac vein	parallels the right coronary artery and drains blood from the posterior surfaces of the right atrium and ventricle; drains into the great cardiac vein
sulcus	(plural = sulci) fat-filled groove visible on the surface of the heart; coronary vessels are also located in these areas
superior vena cava	large systemic vein that returns blood to the heart from the superior portion of the body
systemic circuit	blood flow to and from virtually all of the tissues of the body
trabeculae carneae	ridges of muscle covered by endocardium located in the ventricles
tricuspid valve	term used most often in clinical settings for the right atrioventricular valve
valve	in the cardiovascular system, a specialized structure located within the heart or vessels that ensures one-way flow of blood
ventricle	one of the primary pumping chambers of the heart located in the lower portion of the heart; the left ventricle is the major pumping chamber on the lower left side of the heart that ejects blood into the systemic circuit via the aorta and receives blood from the left atrium; the right ventricle is the major pumping chamber on the lower right side of the heart that ejects blood into the pulmonary circuit via the pulmonary trunk and receives blood from the right atrium
artificial pacemaker	medical device that transmits electrical signals to the heart to ensure that it contracts and pumps blood to the body
atrioventricular bundle	(also, bundle of His) group of specialized myocardial conductile cells that transmit the impulse from the AV node through the interventricular septum; form the left and right atrioventricular bundle branches
atrioventricular bundle branches	(also, left or right bundle branches) specialized myocardial conductile cells that arise from the bifurcation of the atrioventricular bundle and pass through the interventricular septum; lead to the Purkinje fibers and also to the right papillary muscle via the moderator band
atrioventricular (AV) node	clump of myocardial cells located in the inferior portion of the right atrium within the atrioventricular septum; receives the impulse from the SA node, pauses, and then transmits it into specialized conducting cells within the interventricular septum
autorhythmicity	ability of cardiac muscle to initiate its own electrical impulse that triggers the mechanical contraction that pumps blood at a fixed pace without nervous or endocrine control
Bachmann’s bundle	(also, interatrial band) group of specialized conducting cells that transmit the impulse directly from the SA node in the right atrium to the left atrium
bundle of His	(also, atrioventricular bundle) group of specialized myocardial conductile cells that transmit the impulse from the AV node through the interventricular septum; form the left and right atrioventricular bundle branches
electrocardiogram (ECG)	surface recording of the electrical activity of the heart that can be used for diagnosis of irregular heart function; also abbreviated as EKG
heart block	interruption in the normal conduction pathway
interatrial band	(also, Bachmann’s bundle) group of specialized conducting cells that transmit the impulse directly from the SA node in the right atrium to the left atrium
intercalated disc	physical junction between adjacent cardiac muscle cells; consisting of desmosomes, specialized linking proteoglycans, and gap junctions that allow passage of ions between the two cells
internodal pathways	specialized conductile cells within the atria that transmit the impulse from the SA node throughout the myocardial cells of the atrium and to the AV node
myocardial conducting cells	specialized cells that transmit electrical impulses throughout the heart and trigger contraction by the myocardial contractile cells
myocardial contractile cells	bulk of the cardiac muscle cells in the atria and ventricles that conduct impulses and contract to propel blood
P wave	component of the electrocardiogram that represents the depolarization of the atria
pacemaker	cluster of specialized myocardial cells known as the SA node that initiates the sinus rhythm
Purkinje fibers	(also, subendocardial conducting network) specialized myocardial conducting fibers that arise from the bundle branches and spread the impulse to the myocardial contraction fibers of the ventricles
QRS complex	component of the electrocardiogram that represents the depolarization of the ventricles and includes, as a component, the repolarization of the atria
sinoatrial (SA) node	known as the pacemaker, a specialized clump of myocardial conducting cells located in the superior portion of the right atrium that has the highest inherent rate of depolarization that then spreads throughout the heart
sinus rhythm	normal contractile pattern of the heart
subendocardial conducting network	(also, Purkinje fibers) specialized myocardial conducting fibers that arise from the bundle branches and spread the impulse to the myocardial contraction fibers of the ventricles
T wave	component of the electrocardiogram that represents the repolarization of the ventricles
cardiac cycle	period of time between the onset of atrial contraction (atrial systole) and ventricular relaxation (ventricular diastole)
diastole	period of time when the heart muscle is relaxed and the chambers fill with blood
end diastolic volume (EDV)	(also, preload) the amount of blood in the ventricles at the end of atrial systole just prior to ventricular contraction
end systolic volume (ESV)	amount of blood remaining in each ventricle following systole
heart sounds	sounds heard via auscultation with a stethoscope of the closing of the atrioventricular valves (“lub”) and semilunar valves (“dub”)
isovolumetric contraction	(also, isovolumic contraction) initial phase of ventricular contraction in which tension and pressure in the ventricle increase, but no blood is pumped or ejected from the heart
isovolumetric ventricular relaxation phase	(also, isovolumic ventricular relaxation phase) initial phase of the ventricular diastole when pressure in the ventricles drops below pressure in the two major arteries, the pulmonary trunk, and the aorta, and blood attempts to flow back into the ventricles, closing the two semilunar valves
murmur	unusual heart sound detected by auscultation; typically related to septal or valve defects
preload	(also, end diastolic volume) amount of blood in the ventricles at the end of atrial systole just prior to ventricular contraction
systole	period of time when the heart muscle is contracting
ventricular ejection phase	second phase of ventricular systole during which blood is pumped from the ventricle
bulbus cordis	portion of the primitive heart tube that will eventually develop into the right ventricle
cardiogenic area	area near the head of the embryo where the heart begins to develop 18–19 days after fertilization
cardiogenic cords	two strands of tissue that form within the cardiogenic area
endocardial tubes	stage in which lumens form within the expanding cardiogenic cords, forming hollow structures
heart bulge	prominent feature on the anterior surface of the heart, reflecting early cardiac development
mesoderm	one of the three primary germ layers that differentiate early in embryonic development
primitive atrium	portion of the primitive heart tube that eventually becomes the anterior portions of both the right and left atria, and the two auricles
primitive heart tube	singular tubular structure that forms from the fusion of the two endocardial tubes
primitive ventricle	portion of the primitive heart tube that eventually forms the left ventricle
sinus venosus	develops into the posterior portion of the right atrium, the SA node, and the coronary sinus
truncus arteriosus	portion of the primitive heart that will eventually divide and give rise to the ascending aorta and pulmonary trunk
arteriole	(also, resistance vessel) very small artery that leads to a capillary
arteriovenous anastomosis	short vessel connecting an arteriole directly to a venule and bypassing the capillary beds
artery	blood vessel that conducts blood away from the heart; may be a conducting or distributing vessel
capacitance	ability of a vein to distend and store blood
capacitance vessels	veins
capillary	smallest of blood vessels where physical exchange occurs between the blood and tissue cells surrounded by interstitial fluid
capillary bed	network of 10–100 capillaries connecting arterioles to venules
continuous capillary	most common type of capillary, found in virtually all tissues except epithelia and cartilage; contains very small gaps in the endothelial lining that permit exchange
elastic artery	(also, conducting artery) artery with abundant elastic fibers located closer to the heart, which maintains the pressure gradient and conducts blood to smaller branches
external elastic membrane	membrane composed of elastic fibers that separates the tunica media from the tunica externa; seen in larger arteries
fenestrated capillary	type of capillary with pores or fenestrations in the endothelium that allow for rapid passage of certain small materials
internal elastic membrane	membrane composed of elastic fibers that separates the tunica intima from the tunica media; seen in larger arteries
lumen	interior of a tubular structure such as a blood vessel or a portion of the alimentary canal through which blood, chyme, or other substances travel
metarteriole	short vessel arising from a terminal arteriole that branches to supply a capillary bed
microcirculation	blood flow through the capillaries
muscular artery	(also, distributing artery) artery with abundant smooth muscle in the tunica media that branches to distribute blood to the arteriole network
nervi vasorum	small nerve fibers found in arteries and veins that trigger contraction of the smooth muscle in their walls
perfusion	distribution of blood into the capillaries so the tissues can be supplied
precapillary sphincters	circular rings of smooth muscle that surround the entrance to a capillary and regulate blood flow into that capillary
sinusoid capillary	rarest type of capillary, which has extremely large intercellular gaps in the basement membrane in addition to clefts and fenestrations; found in areas such as the bone marrow and liver where passage of large molecules occurs
thoroughfare channel	continuation of the metarteriole that enables blood to bypass a capillary bed and flow directly into a venule, creating a vascular shunt
tunica externa	(also, tunica adventitia) outermost layer or tunic of a vessel (except capillaries)
tunica intima	(also, tunica interna) innermost lining or tunic of a vessel
tunica media	middle layer or tunic of a vessel (except capillaries)
vasa vasorum	small blood vessels located within the walls or tunics of larger vessels that supply nourishment to and remove wastes from the cells of the vessels
vascular shunt	continuation of the metarteriole and thoroughfare channel that allows blood to bypass the capillary beds to flow directly from the arterial to the venous circulation
vasoconstriction	constriction of the smooth muscle of a blood vessel, resulting in a decreased vascular diameter
vasodilation	relaxation of the smooth muscle in the wall of a blood vessel, resulting in an increased vascular diameter
vasomotion	irregular, pulsating flow of blood through capillaries and related structures
vein	blood vessel that conducts blood toward the heart
venous reserve	volume of blood contained within systemic veins in the integument, bone marrow, and liver that can be returned to the heart for circulation, if needed
venule	small vessel leading from the capillaries to veins
blood flow	movement of blood through a vessel, tissue, or organ that is usually expressed in terms of volume per unit of time
blood pressure	force exerted by the blood against the wall of a vessel or heart chamber; can be described with the more generic term hydrostatic pressure
compliance	degree to which a blood vessel can stretch as opposed to being rigid
diastolic pressure	lower number recorded when measuring arterial blood pressure; represents the minimal value corresponding to the pressure that remains during ventricular relaxation
hypoxia	lack of oxygen supply to the tissues
ischemia	insufficient blood flow to the tissues
pulse	alternating expansion and recoil of an artery as blood moves through the vessel; an indicator of heart rate
pulse pressure	difference between the systolic and diastolic pressures
resistance	any condition or parameter that slows or counteracts the flow of blood
respiratory pump	increase in the volume of the thorax during inhalation that decreases air pressure, enabling venous blood to flow into the thoracic region, then exhalation increases pressure, moving blood into the atria
skeletal muscle pump	effect on increasing blood pressure within veins by compression of the vessel caused by the contraction of nearby skeletal muscle
systolic pressure	larger number recorded when measuring arterial blood pressure; represents the maximum value following ventricular contraction
vascular tone	contractile state of smooth muscle in a blood vessel
abdominal aorta	portion of the aorta inferior to the aortic hiatus and superior to the common iliac arteries
adrenal artery	branch of the abdominal aorta; supplies blood to the adrenal (suprarenal) glands
adrenal vein	drains the adrenal or suprarenal glands that are immediately superior to the kidneys; the right adrenal vein enters the inferior vena cava directly and the left adrenal vein enters the left renal vein
anterior cerebral artery	arises from the internal carotid artery; supplies the frontal lobe of the cerebrum
anterior communicating artery	anastomosis of the right and left internal carotid arteries; supplies blood to the brain
anterior tibial artery	branches from the popliteal artery; supplies blood to the anterior tibial region; becomes the dorsalis pedis artery
anterior tibial vein	forms from the dorsal venous arch; drains the area near the tibialis anterior muscle and leads to the popliteal vein
aorta	largest artery in the body, originating from the left ventricle and descending to the abdominal region where it bifurcates into the common iliac arteries at the level of the fourth lumbar vertebra; arteries originating from the aorta distribute blood to virtually all tissues of the body
aortic arch	arc that connects the ascending aorta to the descending aorta; ends at the intervertebral disk between the fourth and fifth thoracic vertebrae
aortic hiatus	opening in the diaphragm that allows passage of the thoracic aorta into the abdominal region where it becomes the abdominal aorta
arterial circle	(also, circle of Willis) anastomosis located at the base of the brain that ensures continual blood supply; formed from branches of the internal carotid and vertebral arteries; supplies blood to the brain
ascending aorta	initial portion of the aorta, rising from the left ventricle for a distance of approximately 5 cm
axillary artery	continuation of the subclavian artery as it penetrates the body wall and enters the axillary region; supplies blood to the region near the head of the humerus (humeral circumflex arteries); the majority of the vessel continues into the brachium and becomes the brachial artery
axillary vein	major vein in the axillary region; drains the upper limb and becomes the subclavian vein
azygos vein	originates in the lumbar region and passes through the diaphragm into the thoracic cavity on the right side of the vertebral column; drains blood from the intercostal veins, esophageal veins, bronchial veins, and other veins draining the mediastinal region; leads to the superior vena cava
basilar artery	formed from the fusion of the two vertebral arteries; sends branches to the cerebellum, brain stem, and the posterior cerebral arteries; the main blood supply to the brain stem
basilic vein	superficial vein of the arm that arises from the palmar venous arches, intersects with the median cubital vein, parallels the ulnar vein, and continues into the upper arm; along with the brachial vein, it leads to the axillary vein
brachial artery	continuation of the axillary artery in the brachium; supplies blood to much of the brachial region; gives off several smaller branches that provide blood to the posterior surface of the arm in the region of the elbow; bifurcates into the radial and ulnar arteries at the coronoid fossa
brachial vein	deeper vein of the arm that forms from the radial and ulnar veins in the lower arm; leads to the axillary vein
brachiocephalic artery	single vessel located on the right side of the body; the first vessel branching from the aortic arch; gives rise to the right subclavian artery and the right common carotid artery; supplies blood to the head, neck, upper limb, and wall of the thoracic region
brachiocephalic vein	one of a pair of veins that form from a fusion of the external and internal jugular veins and the subclavian vein; subclavian, external and internal jugulars, vertebral, and internal thoracic veins lead to it; drains the upper thoracic region and flows into the superior vena cava
bronchial artery	systemic branch from the aorta that provides oxygenated blood to the lungs in addition to the pulmonary circuit
bronchial vein	drains the systemic circulation from the lungs and leads to the azygos vein
cavernous sinus	enlarged vein that receives blood from most of the other cerebral veins and the eye socket, and leads to the petrosal sinus
celiac trunk	(also, celiac artery) major branch of the abdominal aorta; gives rise to the left gastric artery, the splenic artery, and the common hepatic artery that forms the hepatic artery to the liver, the right gastric artery to the stomach, and the cystic artery to the gall bladder
cephalic vein	superficial vessel in the upper arm; leads to the axillary vein
cerebrovascular accident (CVA)	blockage of blood flow to the brain; also called a stroke
circle of Willis	(also, arterial circle) anastomosis located at the base of the brain that ensures continual blood supply; formed from branches of the internal carotid and vertebral arteries; supplies blood to the brain
common carotid artery	right common carotid artery arises from the brachiocephalic artery, and the left common carotid arises from the aortic arch; gives rise to the external and internal carotid arteries; supplies the respective sides of the head and neck
common hepatic artery	branch of the celiac trunk that forms the hepatic artery, the right gastric artery, and the cystic artery
common iliac artery	branch of the aorta that leads to the internal and external iliac arteries
common iliac vein	one of a pair of veins that flows into the inferior vena cava at the level of L5; the left common iliac vein drains the sacral region; divides into external and internal iliac veins near the inferior portion of the sacroiliac joint
cystic artery	branch of the common hepatic artery; supplies blood to the gall bladder
deep femoral artery	branch of the femoral artery; gives rise to the lateral circumflex arteries
deep femoral vein	drains blood from the deeper portions of the thigh and leads to the femoral vein
descending aorta	portion of the aorta that continues downward past the end of the aortic arch; subdivided into the thoracic aorta and the abdominal aorta
digital arteries	formed from the superficial and deep palmar arches; supply blood to the digits
digital veins	drain the digits and feed into the palmar arches of the hand and dorsal venous arch of the foot
dorsal arch	(also, arcuate arch) formed from the anastomosis of the dorsalis pedis artery and medial and plantar arteries; branches supply the distal portions of the foot and digits
dorsal venous arch	drains blood from digital veins and vessels on the superior surface of the foot
dorsalis pedis artery	forms from the anterior tibial artery; branches repeatedly to supply blood to the tarsal and dorsal regions of the foot
esophageal artery	branch of the thoracic aorta; supplies blood to the esophagus
esophageal vein	drains the inferior portions of the esophagus and leads to the azygos vein
external carotid artery	arises from the common carotid artery; supplies blood to numerous structures within the face, lower jaw, neck, esophagus, and larynx
external iliac artery	branch of the common iliac artery that leaves the body cavity and becomes a femoral artery; supplies blood to the lower limbs
external iliac vein	formed when the femoral vein passes into the body cavity; drains the legs and leads to the common iliac vein
external jugular vein	one of a pair of major veins located in the superficial neck region that drains blood from the more superficial portions of the head, scalp, and cranial regions, and leads to the subclavian vein
femoral artery	continuation of the external iliac artery after it passes through the body cavity; divides into several smaller branches, the lateral deep femoral artery, and the genicular artery; becomes the popliteal artery as it passes posterior to the knee
femoral circumflex vein	forms a loop around the femur just inferior to the trochanters; drains blood from the areas around the head and neck of the femur; leads to the femoral vein
femoral vein	drains the upper leg; receives blood from the great saphenous vein, the deep femoral vein, and the femoral circumflex vein; becomes the external iliac vein when it crosses the body wall
fibular vein	drains the muscles and integument near the fibula and leads to the popliteal vein
genicular artery	branch of the femoral artery; supplies blood to the region of the knee
gonadal artery	branch of the abdominal aorta; supplies blood to the gonads or reproductive organs; also described as ovarian arteries or testicular arteries, depending upon the sex of the individual
gonadal vein	generic term for a vein draining a reproductive organ; may be either an ovarian vein or a testicular vein, depending on the sex of the individual
great cerebral vein	receives most of the smaller vessels from the inferior cerebral veins and leads to the straight sinus
great saphenous vein	prominent surface vessel located on the medial surface of the leg and thigh; drains the superficial portions of these areas and leads to the femoral vein
hemiazygos vein	smaller vein complementary to the azygos vein; drains the esophageal veins from the esophagus and the left intercostal veins, and leads to the brachiocephalic vein via the superior intercostal vein
hepatic artery proper	branch of the common hepatic artery; supplies systemic blood to the liver
hepatic portal system	specialized circulatory pathway that carries blood from digestive organs to the liver for processing before being sent to the systemic circulation
hepatic vein	drains systemic blood from the liver and flows into the inferior vena cava
inferior mesenteric artery	branch of the abdominal aorta; supplies blood to the distal segment of the large intestine and rectum
inferior phrenic artery	branch of the abdominal aorta; supplies blood to the inferior surface of the diaphragm
inferior vena cava	large systemic vein that drains blood from areas largely inferior to the diaphragm; empties into the right atrium
intercostal artery	branch of the thoracic aorta; supplies blood to the muscles of the thoracic cavity and vertebral column
intercostal vein	drains the muscles of the thoracic wall and leads to the azygos vein
internal carotid artery	arises from the common carotid artery and begins with the carotid sinus; goes through the carotid canal of the temporal bone to the base of the brain; combines with branches of the vertebral artery forming the arterial circle; supplies blood to the brain
internal iliac artery	branch from the common iliac arteries; supplies blood to the urinary bladder, walls of the pelvis, external genitalia, and the medial portion of the femoral region; in females, also provide blood to the uterus and vagina
internal iliac vein	drains the pelvic organs and integument; formed from several smaller veins in the region; leads to the common iliac vein
internal jugular vein	one of a pair of major veins located in the neck region that passes through the jugular foramen and canal, flows parallel to the common carotid artery that is more or less its counterpart; primarily drains blood from the brain, receives the superficial facial vein, and empties into the subclavian vein
internal thoracic artery	(also, mammary artery) arises from the subclavian artery; supplies blood to the thymus, pericardium of the heart, and the anterior chest wall
internal thoracic vein	(also, internal mammary vein) drains the anterior surface of the chest wall and leads to the brachiocephalic vein
lateral circumflex artery	branch of the deep femoral artery; supplies blood to the deep muscles of the thigh and the ventral and lateral regions of the integument
lateral plantar artery	arises from the bifurcation of the posterior tibial arteries; supplies blood to the lateral plantar surfaces of the foot
left gastric artery	branch of the celiac trunk; supplies blood to the stomach
lumbar arteries	branches of the abdominal aorta; supply blood to the lumbar region, the abdominal wall, and spinal cord
lumbar veins	drain the lumbar portion of the abdominal wall and spinal cord; the superior lumbar veins drain into the azygos vein on the right or the hemiazygos vein on the left; blood from these vessels is returned to the superior vena cava rather than the inferior vena cava
maxillary vein	drains blood from the maxillary region and leads to the external jugular vein
medial plantar artery	arises from the bifurcation of the posterior tibial arteries; supplies blood to the medial plantar surfaces of the foot
median antebrachial vein	vein that parallels the ulnar vein but is more medial in location; intertwines with the palmar venous arches
median cubital vein	superficial vessel located in the antecubital region that links the cephalic vein to the basilic vein in the form of a v; a frequent site for a blood draw
median sacral artery	continuation of the aorta into the sacrum
mediastinal artery	branch of the thoracic aorta; supplies blood to the mediastinum
middle cerebral artery	another branch of the internal carotid artery; supplies blood to the temporal and parietal lobes of the cerebrum
middle sacral vein	drains the sacral region and leads to the left common iliac vein
occipital sinus	enlarged vein that drains the occipital region near the falx cerebelli and flows into the left and right transverse sinuses, and also into the vertebral veins
ophthalmic artery	branch of the internal carotid artery; supplies blood to the eyes
ovarian artery	branch of the abdominal aorta; supplies blood to the ovary, uterine (Fallopian) tube, and uterus
ovarian vein	drains the ovary; the right ovarian vein leads to the inferior vena cava and the left ovarian vein leads to the left renal vein
palmar arches	superficial and deep arches formed from anastomoses of the radial and ulnar arteries; supply blood to the hand and digital arteries
palmar venous arches	drain the hand and digits, and feed into the radial and ulnar veins
parietal branches	(also, somatic branches) group of arterial branches of the thoracic aorta; includes those that supply blood to the thoracic cavity, vertebral column, and the superior surface of the diaphragm
pericardial artery	branch of the thoracic aorta; supplies blood to the pericardium
petrosal sinus	enlarged vein that receives blood from the cavernous sinus and flows into the internal jugular vein
phrenic vein	drains the diaphragm; the right phrenic vein flows into the inferior vena cava and the left phrenic vein leads to the left renal vein
plantar arch	formed from the anastomosis of the dorsalis pedis artery and medial and plantar arteries; branches supply the distal portions of the foot and digits
plantar veins	drain the foot and lead to the plantar venous arch
plantar venous arch	formed from the plantar veins; leads to the anterior and posterior tibial veins through anastomoses
popliteal artery	continuation of the femoral artery posterior to the knee; branches into the anterior and posterior tibial arteries
popliteal vein	continuation of the femoral vein behind the knee; drains the region behind the knee and forms from the fusion of the fibular and anterior and posterior tibial veins
posterior cerebral artery	branch of the basilar artery that forms a portion of the posterior segment of the arterial circle; supplies blood to the posterior portion of the cerebrum and brain stem
posterior communicating artery	branch of the posterior cerebral artery that forms part of the posterior portion of the arterial circle; supplies blood to the brain
posterior tibial artery	branch from the popliteal artery that gives rise to the fibular or peroneal artery; supplies blood to the posterior tibial region
posterior tibial vein	forms from the dorsal venous arch; drains the area near the posterior surface of the tibia and leads to the popliteal vein
pulmonary artery	one of two branches, left and right, that divides off from the pulmonary trunk and leads to smaller arterioles and eventually to the pulmonary capillaries
pulmonary circuit	system of blood vessels that provide gas exchange via a network of arteries, veins, and capillaries that run from the heart, through the body, and back to the lungs
pulmonary trunk	single large vessel exiting the right ventricle that divides to form the right and left pulmonary arteries
pulmonary veins	two sets of paired vessels, one pair on each side, that are formed from the small venules leading away from the pulmonary capillaries that flow into the left atrium
radial artery	formed at the bifurcation of the brachial artery; parallels the radius; gives off smaller branches until it reaches the carpal region where it fuses with the ulnar artery to form the superficial and deep palmar arches; supplies blood to the lower arm and carpal region
radial vein	parallels the radius and radial artery; arises from the palmar venous arches and leads to the brachial vein
renal artery	branch of the abdominal aorta; supplies each kidney
renal vein	largest vein entering the inferior vena cava; drains the kidneys and leads to the inferior vena cava
right gastric artery	branch of the common hepatic artery; supplies blood to the stomach
sigmoid sinuses	enlarged veins that receive blood from the transverse sinuses; flow through the jugular foramen and into the internal jugular vein
small saphenous vein	located on the lateral surface of the leg; drains blood from the superficial regions of the lower leg and foot, and leads to the popliteal vein
splenic artery	branch of the celiac trunk; supplies blood to the spleen
straight sinus	enlarged vein that drains blood from the brain; receives most of the blood from the great cerebral vein and flows into the left or right transverse sinus
subclavian artery	right subclavian arises from the brachiocephalic artery, whereas the left subclavian artery arises from the aortic arch; gives rise to the internal thoracic, vertebral, and thyrocervical arteries; supplies blood to the arms, chest, shoulders, back, and central nervous system
subclavian vein	located deep in the thoracic cavity; becomes the axillary vein as it enters the axillary region; drains the axillary and smaller local veins near the scapular region; leads to the brachiocephalic vein
subscapular vein	drains blood from the subscapular region and leads to the axillary vein
superior mesenteric artery	branch of the abdominal aorta; supplies blood to the small intestine (duodenum, jejunum, and ileum), the pancreas, and a majority of the large intestine
superior phrenic artery	branch of the thoracic aorta; supplies blood to the superior surface of the diaphragm
superior sagittal sinus	enlarged vein located midsagittally between the meningeal and periosteal layers of the dura mater within the falx cerebri; receives most of the blood drained from the superior surface of the cerebrum and leads to the inferior jugular vein and the vertebral vein
superior vena cava	large systemic vein; drains blood from most areas superior to the diaphragm; empties into the right atrium
temporal vein	drains blood from the temporal region and leads to the external jugular vein
testicular artery	branch of the abdominal aorta; will ultimately travel outside the body cavity to the testes and form one component of the spermatic cord
testicular vein	drains the testes and forms part of the spermatic cord; the right testicular vein empties directly into the inferior vena cava and the left testicular vein empties into the left renal vein
thoracic aorta	portion of the descending aorta superior to the aortic hiatus
thyrocervical artery	arises from the subclavian artery; supplies blood to the thyroid, the cervical region, the upper back, and shoulder
transient ischemic attack (TIA)	temporary loss of neurological function caused by a brief interruption in blood flow; also known as a mini-stroke
transverse sinuses	pair of enlarged veins near the lambdoid suture that drain the occipital, sagittal, and straight sinuses, and leads to the sigmoid sinuses
trunk	large vessel that gives rise to smaller vessels
ulnar artery	formed at the bifurcation of the brachial artery; parallels the ulna; gives off smaller branches until it reaches the carpal region where it fuses with the radial artery to form the superficial and deep palmar arches; supplies blood to the lower arm and carpal region
ulnar vein	parallels the ulna and ulnar artery; arises from the palmar venous arches and leads to the brachial vein
vertebral artery	arises from the subclavian artery and passes through the vertebral foramen through the foramen magnum to the brain; joins with the internal carotid artery to form the arterial circle; supplies blood to the brain and spinal cord
vertebral vein	arises from the base of the brain and the cervical region of the spinal cord; passes through the intervertebral foramina in the cervical vertebrae; drains smaller veins from the cranium, spinal cord, and vertebrae, and leads to the brachiocephalic vein; counterpart of the vertebral artery
visceral branches	branches of the descending aorta that supply blood to the viscera
angioblasts	stem cells that give rise to blood vessels
angiogenesis	development of new blood vessels from existing vessels
blood islands	masses of developing blood vessels and formed elements from mesodermal cells scattered throughout the embryonic disc
ductus arteriosus	shunt in the fetal pulmonary trunk that diverts oxygenated blood back to the aorta
ductus venosus	shunt that causes oxygenated blood to bypass the fetal liver on its way to the inferior vena cava
foramen ovale	shunt that directly connects the right and left atria and helps to divert oxygenated blood from the fetal pulmonary circuit
hemangioblasts	embryonic stem cells that appear in the mesoderm and give rise to both angioblasts and pluripotent stem cells
umbilical arteries	pair of vessels that runs within the umbilical cord and carries fetal blood low in oxygen and high in waste to the placenta for exchange with maternal blood
umbilical vein	single vessel that originates in the placenta and runs within the umbilical cord, carrying oxygen- and nutrient-rich blood to the fetal heart
vascular tubes	rudimentary blood vessels in a developing fetus
1^st line of defense	temporal classification for the barrier defenses of the immune system that serve to prevent infection
2^nd line of defense	temporal classification for the innate immune response that rapidly, but nonspecifically responds to pathogens to slow the spread of infection and also promotes healing after tissue damage
3^rd line of defense	temporal classification for the adaptive immune response that responds more slowly, but also specifically and more effectively to eradicate infection
adaptive immune response	relatively slow but very specific and effective immune response controlled by lymphocytes
afferent lymphatic vessels	lead into a lymph node
antibody	antigen-specific protein secreted by plasma cells; immunoglobulin
antigen	molecule recognized by the receptors of B and T lymphocytes
barrier defenses	antipathogen defenses deriving from a barrier that physically prevents pathogens from entering the body to establish an infection
B cells	lymphocytes that act by differentiating into an antibody-secreting plasma cell
bone marrow	tissue found inside bones; the site of all blood cell differentiation and maturation of B lymphocytes
chyle	lipid-rich lymph inside the lymphatic capillaries of the small intestine
cisterna chyli	bag-like vessel that forms the beginning of the thoracic duct
efferent lymphatic vessels	lead out of a lymph node
germinal centers	clusters of rapidly proliferating B cells found in secondary lymphoid tissues
high endothelial venules	vessels containing unique endothelial cells specialized to allow migration of lymphocytes from the blood to the lymph node
immune system	series of barriers, cells, and soluble mediators that combine to response to infections of the body with pathogenic organisms
innate immune response	rapid but relatively nonspecific immune response
lymph	fluid contained within the lymphatic system
lymph node	one of the bean-shaped organs found associated with the lymphatic vessels
lymphatic capillaries	smallest of the lymphatic vessels and the origin of lymph flow
lymphatic system	network of lymphatic vessels, lymph nodes, and ducts that carries lymph from the tissues and back to the bloodstream.
lymphatic trunks	large lymphatics that collect lymph from smaller lymphatic vessels and empties into the blood via lymphatic ducts
lymphocytes	white blood cells characterized by a large nucleus and small rim of cytoplasm
lymphoid nodules	unencapsulated patches of lymphoid tissue found throughout the body
mucosa-associated lymphoid tissue (MALT)	lymphoid nodule associated with the mucosa
naïve lymphocyte	mature B or T cell that has not yet encountered antigen for the first time
natural killer cell (NK)	cytotoxic lymphocyte of innate immune response
plasma cell	differentiated B cell that is actively secreting antibody
primary lymphoid organ	site where lymphocytes mature and proliferate; red bone marrow and thymus gland
right lymphatic duct	drains lymph fluid from the upper right side of body into the right subclavian vein
secondary lymphoid organs	sites where lymphocytes mount adaptive immune responses; examples include lymph nodes and spleen
spleen	secondary lymphoid organ that filters pathogens from the blood (white pulp) and removes degenerating or damaged blood cells (red pulp)
T cell	lymphocyte that acts by secreting molecules that regulate the immune system or by causing the destruction of foreign cells, viruses, and cancer cells
thoracic duct	large duct that drains lymph from the lower limbs, left thorax, left upper limb, and the left side of the head
thymocyte	immature T cell found in the thymus
thymus	primary lymphoid organ; where T lymphocytes proliferate and mature
tonsils	lymphoid nodules associated with the nasopharynx
acute inflammation	inflammation occurring for a limited time period; rapidly developing
antigen-presenting cell (APC)	cell that presents a fragment of an antigen to T cells to induce an adaptive immune response
chemokine	soluble, long-range, cell-to-cell communication molecule
chronic inflammation	inflammation occurring for long periods of time
complement	enzymatic cascade of constitutive blood proteins that have antipathogen effects, including the direct killing of bacteria
cytokine	soluble, short-range, cell-to-cell communication molecule
dendritic cell	phagocyte and antigen-presenting cell (APC) typically found in epithelial tissues such as the epidermis
early induced immune response	includes antimicrobial proteins stimulated during the first several days of an infection
histamine	vasoactive mediator in granules of mast cells and is the primary cause of allergies and anaphylactic shock
inflammation	basic innate immune response characterized by heat, redness, pain, and swelling
interferons	early induced proteins made in virally infected cells that cause nearby cells to make antiviral proteins
macrophage	ameoboid phagocyte found in several tissues throughout the body; also an APC
mast cell	cell found in the skin and the lining of body cells that contains cytoplasmic granules with vasoactive mediators such as histamine
monocyte	precursor to macrophages and dendritic cells seen in the blood
neutrophil	phagocytic white blood cell recruited from the bloodstream to the site of infection via the bloodstream
phagocytosis	movement of material from the outside to the inside of the cells via vesicles made from invaginations of the plasma membrane
active immunity	immunity developed from an individual’s own immune system
central tolerance	B cell tolerance induced in immature B cells of the bone marrow
clonal anergy	process whereby B cells that react to soluble antigens in bone marrow are made nonfunctional
clonal deletion	removal of self-reactive B cells by inducing apoptosis
immunoglobulin	protein antibody; occurs as one of five main classes
passive immunity	transfer of immunity to a pathogen to an individual that lacks immunity to this pathogen usually by the injection of antibodies
peripheral tolerance	mature B cell made tolerant by lack of T cell help
T cell-dependent antigen	antigen that binds to B cells, which requires signals from T cells to make antibody
T cell-independent antigen	binds to B cells, which do not require signals from T cells to make antibody
antigen presentation	binding of processed antigen to the protein-binding cleft of a major histocompatibility complex molecule
clone	group of lymphocytes sharing the same antigen receptor
clonal expansion	growth of a clone of selected lymphocytes
clonal selection	stimulating growth of lymphocytes that have specific receptors
constant region domain	part of a lymphocyte antigen receptor that does not vary much between different receptor types
cytotoxic T cells (Tc, T8, or CD8⁺ T cells)	T lymphocytes with the ability to induce apoptosis in target cells
effector T cells	immune cells with a direct, adverse effect on a pathogen
helper T cells (Th, T4, or CD4⁺ T cells)	T cells that secrete cytokines to enhance other immune responses, involved in activation of both B and T cell lymphocytes
immunological memory	ability of the adaptive immune response to mount a stronger and faster immune response upon re-exposure to a pathogen
memory T cells	long-lived immune cell reserved for future exposure to an pathogen
primary adaptive response	immune system’s response to the first exposure to a pathogen
regulatory T cells (Treg)	(also, suppressor T cells) class of CD4 T cells that regulates other T cell responses
secondary adaptive response	immune response observed upon re-exposure to a pathogen, which is stronger and faster than a primary response
neutralization	inactivation of a virus by the binding of specific antibody
seroconversion	clearance of pathogen in the serum and the simultaneous rise of serum antibody
severe combined immunodeficiency disease (SCID)	genetic mutation that affects both T cell and B cell arms of the immune response
ala	(plural = alae) small, flaring structure of a nostril that forms the lateral side of the external nares
alar cartilage	cartilage that supports the apex of the nose and helps shape the nares; it is connected to the septal cartilage and connective tissue of the alae
alveolar duct	small tube that leads from the terminal bronchiole to the respiratory bronchiole and is the point of attachment for alveoli
alveolar macrophage	immune system cell of the alveolus that removes debris and pathogens
alveolar pore	opening that allows airflow between neighboring alveoli
alveolar sac	cluster of alveoli
alveolus	small, grape-like sac that performs gas exchange in the lungs
apex	tip of the external nose
bronchial tree	collective name for the multiple branches of the bronchi and bronchioles of the respiratory system
bridge	portion of the external nose that lies in the area of the nasal bones
bronchiole	branch of bronchi that are 1 mm or less in diameter and terminate at alveolar sacs
bronchus	tube connected to the trachea that branches into many subsidiaries and provides a passageway for air to enter and leave the lungs
conducting zone	region of the respiratory system that includes the organs and structures that provide passageways for air and are not directly involved in gas exchange
cricoid cartilage	portion of the larynx composed of a ring of cartilage with a wide posterior region and a thinner anterior region; attached to the esophagus
dorsum nasi	intermediate portion of the external nose that connects the bridge to the apex and is supported by the nasal bone
epiglottis	leaf-shaped piece of elastic cartilage that is a portion of the larynx that swings to close the trachea during swallowing
external nose	region of the nose that is easily visible to others
fauces	portion of the posterior oral cavity that connects the oral cavity to the oropharynx
fibroelastic membrane	specialized membrane that connects the ends of the C-shape cartilage in the trachea; contains smooth muscle fibers
glottis	opening between the vocal folds through which air passes when producing speech
laryngeal prominence	region where the two lamina of the thyroid cartilage join, forming a protrusion known as “Adam’s apple”
laryngopharynx	portion of the pharynx bordered by the oropharynx superiorly and esophagus and trachea inferiorly; serves as a route for both air and food
larynx	cartilaginous structure that produces the voice, prevents food and beverages from entering the trachea, and regulates the volume of air that enters and leaves the lungs
lingual tonsil	lymphoid tissue located at the base of the tongue
meatus	one of three recesses (superior, middle, and inferior) in the nasal cavity attached to the conchae that increase the surface area of the nasal cavity
naris	(plural = nares) opening of the nostrils
nasal bone	bone of the skull that lies under the root and bridge of the nose and is connected to the frontal and maxillary bones
nasal septum	wall composed of bone and cartilage that separates the left and right nasal cavities
nasopharynx	portion of the pharynx flanked by the conchae and oropharynx that serves as an airway
oropharynx	portion of the pharynx flanked by the nasopharynx, oral cavity, and laryngopharynx that is a passageway for both air and food
palatine tonsil	one of the paired structures composed of lymphoid tissue located anterior to the uvula at the roof of isthmus of the fauces
paranasal sinus	one of the cavities within the skull that is connected to the conchae that serve to warm and humidify incoming air, produce mucus, and lighten the weight of the skull; consists of frontal, maxillary, sphenoidal, and ethmoidal sinuses
pharyngeal tonsil	structure composed of lymphoid tissue located in the nasopharynx
pharynx	region of the conducting zone that forms a tube of skeletal muscle lined with respiratory epithelium; located between the nasal conchae and the esophagus and trachea
philtrum	concave surface of the face that connects the apex of the nose to the top lip
pulmonary surfactant	substance composed of phospholipids and proteins that reduces the surface tension of the alveoli; made by type II alveolar cells
respiratory bronchiole	specific type of bronchiole that leads to alveolar sacs
respiratory epithelium	ciliated lining of much of the conducting zone that is specialized to remove debris and pathogens, and produce mucus
respiratory membrane	alveolar and capillary wall together, which form an air-blood barrier that facilitates the simple diffusion of gases
respiratory zone	includes structures of the respiratory system that are directly involved in gas exchange
root	region of the external nose between the eyebrows
thyroid cartilage	largest piece of cartilage that makes up the larynx and consists of two lamina
trachea	tube composed of cartilaginous rings and supporting tissue that connects the lung bronchi and the larynx; provides a route for air to enter and exit the lung
trachealis muscle	smooth muscle located in the fibroelastic membrane of the trachea
true vocal cord	one of the pair of folded, white membranes that have a free inner edge that oscillates as air passes through to produce sound
type I alveolar cell	squamous epithelial cells that are the major cell type in the alveolar wall; highly permeable to gases
type II alveolar cell	cuboidal epithelial cells that are the minor cell type in the alveolar wall; secrete pulmonary surfactant
vestibular fold	part of the folded region of the glottis composed of mucous membrane; supports the epiglottis during swallowing
bronchoconstriction	decrease in the size of the bronchiole due to contraction of the muscular wall
bronchodilation	increase in the size of the bronchiole due to contraction of the muscular wall
cardiac notch	indentation on the surface of the left lung that allows space for the heart
hilum	concave structure on the mediastinal surface of the lungs where blood vessels, lymphatic vessels, nerves, and a bronchus enter the lung
lung	organ of the respiratory system that performs gas exchange
parietal pleura	outermost layer of the pleura that connects to the thoracic wall, mediastinum, and diaphragm
pleural cavity	space between the visceral and parietal pleurae
pleural fluid	substance that acts as a lubricant for the visceral and parietal layers of the pleura during the movement of breathing
pulmonary artery	artery that arises from the pulmonary trunk and carries deoxygenated, arterial blood to the alveoli
pulmonary plexus	network of autonomic nervous system fibers found near the hilum of the lung
visceral pleura	innermost layer of the pleura that is superficial to the lungs and extends into the lung fissures
bronchial bud	structure in the developing embryo that forms when the laryngotracheal bud extends and branches to form two bulbous structures
foregut	endoderm of the embryo towards the head region
laryngotracheal	bud forms from the lung bud, has a tracheal end and bulbous bronchial buds at the distal end
lung bud	median dome that forms from the endoderm of the foregut
olfactory pit	invaginated ectodermal tissue in the anterior portion of the head region of an embryo that will form the nasal cavity
accessory digestive organ	includes teeth, tongue, salivary glands, gallbladder, liver, and pancreas
alimentary canal	continuous muscular digestive tube that extends from the mouth to the anus
motility	movement of food through the GI tract
mucosa	innermost lining of the alimentary canal
muscularis	muscle (skeletal or smooth) layer of the alimentary canal wall
myenteric plexus	(plexus of Auerbach) major nerve supply to alimentary canal wall; controls motility
retroperitoneal	located posterior to the peritoneum
serosa	outermost layer of the alimentary canal wall present in regions within the abdominal cavity
submucosa	layer of dense connective tissue in the alimentary canal wall that binds the overlying mucosa to the underlying muscularis
submucosal plexus	(plexus of Meissner) nerve supply that regulates activity of glands and smooth muscle
absorption	passage of digested products from the intestinal lumen through mucosal cells and into the bloodstream or lacteals
chemical digestion	enzymatic breakdown of food
chyme	soupy liquid created when food is mixed with digestive juices
defecation	elimination of undigested substances from the body in the form of feces
ingestion	taking food into the GI tract through the mouth
mastication	chewing
mechanical digestion	chewing, mixing, and segmentation that prepares food for chemical digestion
peristalsis	muscular contractions and relaxations that propel food through the GI tract
propulsion	voluntary process of swallowing and the involuntary process of peristalsis that moves food through the digestive tract
segmentation	alternating contractions and relaxations of non-adjacent segments of the intestine that move food forward and backward, breaking it apart and mixing it with digestive juices
bolus	mass of chewed food
cementum	bone-like tissue covering the root of a tooth
crown	portion of tooth visible superior to the gum line
cuspid	(also, canine) pointed tooth used for tearing and shredding food
deciduous tooth	one of 20 “baby teeth”
deglutition	three-stage process of swallowing
dens	tooth
dentin	bone-like tissue immediately deep to the enamel of the crown or cementum of the root of a tooth
dentition	set of teeth
enamel	covering of the dentin of the crown of a tooth
esophagus	muscular tube that runs from the pharynx to the stomach
fauces	opening between the oral cavity and the oropharynx
gingiva	gum
incisor	midline, chisel-shaped tooth used for cutting into food
labium	lip
labial frenulum	midline mucous membrane fold that attaches the inner surface of the lips to the gums
laryngopharynx	part of the pharynx that functions in respiration and digestion
lingual frenulum	mucous membrane fold that attaches the bottom of the tongue to the floor of the mouth
lingual lipase	digestive enzyme from glands in the tongue that acts on triglycerides
lower esophageal sphincter	smooth muscle sphincter that regulates food movement from the esophagus to the stomach
molar	tooth used for crushing and grinding food
oral cavity	(also, buccal cavity) mouth
oral vestibule	part of the mouth bounded externally by the cheeks and lips, and internally by the gums and teeth
oropharynx	part of the pharynx continuous with the oral cavity that functions in respiration and digestion
palatoglossal arch	muscular fold that extends from the lateral side of the soft palate to the base of the tongue
palatopharyngeal arch	muscular fold that extends from the lateral side of the soft palate to the side of the pharynx
parotid gland	one of a pair of major salivary glands located inferior and anterior to the ears
permanent tooth	one of 32 adult teeth
pharynx	throat
premolar	(also, bicuspid) transitional tooth used for mastication, crushing, and grinding food
pulp cavity	deepest portion of a tooth, containing nerve endings and blood vessels
root	portion of a tooth embedded in the alveolar processes beneath the gum line
saliva	aqueous solution of proteins and ions secreted into the mouth by the salivary glands
salivary amylase	digestive enzyme in saliva that acts on starch
salivary gland	an exocrine gland that secretes a digestive fluid called saliva
salivation	secretion of saliva
soft palate	posterior region of the bottom portion of the nasal cavity that consists of skeletal muscle
sublingual gland	one of a pair of major salivary glands located beneath the tongue
submandibular gland	one of a pair of major salivary glands located in the floor of the mouth
tongue	accessory digestive organ of the mouth, the bulk of which is composed of skeletal muscle
upper esophageal sphincter	skeletal muscle sphincter that regulates food movement from the pharynx to the esophagus
voluntary phase	initial phase of deglutition, in which the bolus moves from the mouth to the oropharynx
body	mid-portion of the stomach
cardia	(also, cardiac region) part of the stomach surrounding the cardiac orifice (esophageal hiatus)
cephalic phase	(also, reflex phase) initial phase of gastric secretion that occurs before food enters the stomach
chief cell	gastric gland cell that secretes pepsinogen
enteroendocrine cell	gastric gland cell that releases hormones
fundus	dome-shaped region of the stomach above and to the left of the cardia
G cell	gastrin-secreting enteroendocrine cell
gastric emptying	process by which mixing waves gradually cause the release of chyme into the duodenum
gastric gland	gland in the stomach mucosal epithelium that produces gastric juice
gastric phase	phase of gastric secretion that begins when food enters the stomach
gastric pit	narrow channel formed by the epithelial lining of the stomach mucosa
gastrin	peptide hormone that stimulates secretion of hydrochloric acid and gut motility
hydrochloric acid (HCl)	digestive acid secreted by parietal cells in the stomach
intrinsic factor	glycoprotein required for vitamin B₁₂ absorption in the small intestine
intestinal phase	phase of gastric secretion that begins when chyme enters the intestine
mixing wave	unique type of peristalsis that occurs in the stomach
mucosal barrier	protective barrier that prevents gastric juice from destroying the stomach itself
mucous neck cell	gastric gland cell that secretes a uniquely acidic mucus
parietal cell	gastric gland cell that secretes hydrochloric acid and intrinsic factor
pepsinogen	inactive form of pepsin
pyloric antrum	wider, more superior part of the pylorus
pyloric canal	narrow, more inferior part of the pylorus
pyloric sphincter	sphincter that controls stomach emptying
pylorus	lower, funnel-shaped part of the stomach that is continuous with the duodenum
ruga	fold of alimentary canal mucosa and submucosa in the empty stomach and other organs
stomach	alimentary canal organ that contributes to chemical and mechanical digestion of food from the esophagus before releasing it, as chyme, to the small intestine
anal canal	final segment of the large intestine
anal column	long fold of mucosa in the anal canal
anal sinus	recess between anal columns
appendix	(vermiform appendix) coiled tube attached to the cecum
ascending colon	first region of the colon
bacterial flora	bacteria in the large intestine
brush border	fuzzy appearance of the small intestinal mucosa created by microvilli
cecum	pouch forming the beginning of the large intestine
circular fold	(also, plica circulare) deep fold in the mucosa and submucosa of the small intestine
colon	part of the large intestine between the cecum and the rectum
descending colon	part of the colon between the transverse colon and the sigmoid colon
duodenal gland	(also, Brunner’s gland) mucous-secreting gland in the duodenal submucosa
duodenum	first part of the small intestine, which starts at the pyloric sphincter and ends at the jejunum
epiploic appendage	small sac of fat-filled visceral peritoneum attached to teniae coli
external anal sphincter	voluntary skeletal muscle sphincter in the anal canal
feces	semisolid waste product of digestion
flatus	gas in the intestine
gastrocolic reflex	propulsive movement in the colon activated by the presence of food in the stomach
gastroileal reflex	long reflex that increases the strength of segmentation in the ileum
haustrum	small pouch in the colon created by tonic contractions of teniae coli
haustral contraction	slow segmentation in the large intestine
hepatopancreatic ampulla	(also, ampulla of Vater) bulb-like point in the wall of the duodenum where the bile duct and main pancreatic duct unite
hepatopancreatic sphincter	(also, sphincter of Oddi) sphincter regulating the flow of bile and pancreatic juice into the duodenum
ileocecal sphincter	sphincter located where the small intestine joins with the large intestine
ileum	end of the small intestine between the jejunum and the large intestine
internal anal sphincter	involuntary smooth muscle sphincter in the anal canal
intestinal gland	(also, crypt of Lieberkühn) gland in the small intestinal mucosa that secretes intestinal juice
intestinal juice	mixture of water and mucus that helps absorb nutrients from chyme
jejunum	middle part of the small intestine between the duodenum and the ileum
lacteal	lymphatic capillary in the villi
large intestine	terminal portion of the alimentary canal
left colic flexure	(also, splenic flexure) point where the transverse colon curves below the inferior end of the spleen
main pancreatic duct	(also, duct of Wirsung) duct through which pancreatic juice drains from the pancreas
major duodenal papilla	point at which the hepatopancreatic ampulla opens into the duodenum
mass movement	long, slow, peristaltic wave in the large intestine
mesoappendix	mesentery of the appendix
microvillus	small projection of the plasma membrane of the absorptive cells of the small intestinal mucosa
migrating motility complex	form of peristalsis in the small intestine
motilin	hormone that initiates migrating motility complexes
pectinate line	horizontal line that runs like a ring, perpendicular to the inferior margins of the anal sinuses
rectal valve	one of three transverse folds in the rectum where feces is separated from flatus
rectum	part of the large intestine between the sigmoid colon and anal canal
right colic flexure	(also, hepatic flexure) point, at the inferior surface of the liver, where the ascending colon turns abruptly to the left
saccharolytic fermentation	anaerobic decomposition of carbohydrates
sigmoid colon	end portion of the colon, which terminates at the rectum
small intestine	section of the alimentary canal where most digestion and absorption occurs
tenia coli	one of three smooth muscle bands that make up the longitudinal muscle layer of the muscularis in all of the large intestine except the terminal end
transverse colon	part of the colon between the ascending colon and the descending colon
Valsalva’s maneuver	voluntary contraction of the diaphragm and abdominal wall muscles and closing of the glottis, which increases intra-abdominal pressure and facilitates defecation
villus	projection of the mucosa of the small intestine
accessory duct	(also, duct of Santorini) duct that runs from the pancreas into the duodenum
acinus	cluster of glandular epithelial cells in the pancreas that secretes pancreatic juice in the pancreas
bile	alkaline solution produced by the liver and important for the emulsification of lipids
bile canaliculus	small duct between hepatocytes that collects bile
bilirubin	main bile pigment, which is responsible for the brown color of feces
central vein	vein that receives blood from hepatic sinusoids
common bile duct	structure formed by the union of the common hepatic duct and the gallbladder’s cystic duct
common hepatic duct	duct formed by the merger of the two hepatic ducts
cystic duct	duct through which bile drains and enters the gallbladder
enterohepatic circulation	recycling mechanism that conserves bile salts
enteropeptidase	intestinal brush-border enzyme that activates trypsinogen to trypsin
gallbladder	accessory digestive organ that stores and concentrates bile
hepatic artery	artery that supplies oxygenated blood to the liver
hepatic lobule	hexagonal-shaped structure composed of hepatocytes that radiate outward from a central vein
hepatic portal vein	vein that supplies deoxygenated nutrient-rich blood to the liver
hepatic sinusoid	blood capillaries between rows of hepatocytes that receive blood from the hepatic portal vein and the branches of the hepatic artery
hepatic vein	vein that drains into the inferior vena cava
hepatocytes	major functional cells of the liver
liver	largest gland in the body whose main digestive function is the production of bile
pancreas	accessory digestive organ that secretes pancreatic juice
pancreatic juice	secretion of the pancreas containing digestive enzymes and bicarbonate
porta hepatis	“gateway to the liver” where the hepatic artery and hepatic portal vein enter the liver
portal triad	bile duct, hepatic artery branch, and hepatic portal vein branch
reticuloendothelial cell	(also, Kupffer cell) phagocyte in hepatic sinusoids that filters out material from venous blood from the alimentary canal
Bowman’s capsule	cup-shaped sack lined by a simple squamous epithelium (parietal surface) and specialized cells called podocytes (visceral surface) that participate in the filtration process; receives the filtrate which then passes on to the PCTs
calyces	cup-like structures receiving urine from the collecting ducts where it passes on to the renal pelvis and ureter
cortical nephrons	nephrons with loops of Henle that do not extend into the renal medulla
distal convoluted tubules	portions of the nephron distal to the loop of Henle that receive hyposmotic filtrate from the loop of Henle and empty into collecting ducts
efferent arteriole	arteriole carrying blood from the glomerulus to the capillary beds around the convoluted tubules and loop of Henle; portion of the portal system
glomerulus	tuft of capillaries surrounded by Bowman’s capsule; filters the blood based on size
juxtamedullary nephrons	nephrons adjacent to the border of the cortex and medulla with loops of Henle that extend into the renal medulla
loop of Henle	descending and ascending portions between the proximal and distal convoluted tubules; those of cortical nephrons do not extend into the medulla, whereas those of juxtamedullary nephrons do extend into the medulla
nephrons	functional units of the kidney that carry out all filtration and modification to produce urine; consist of renal corpuscles, proximal and distal convoluted tubules, and descending and ascending loops of Henle; drain into collecting ducts
medulla	inner region of kidney containing the renal pyramids
peritubular capillaries	second capillary bed of the renal portal system; surround the proximal and distal convoluted tubules; associated with the vasa recta
proximal convoluted tubules (PCTs)	tortuous tubules receiving filtrate from Bowman’s capsule; most active part of the nephron in reabsorption and secretion
renal columns	extensions of the renal cortex into the renal medulla; separates the renal pyramids; contains blood vessels and connective tissues
renal corpuscle	consists of the glomerulus and Bowman’s capsule
renal cortex	outer part of kidney containing all of the nephrons; some nephrons have loops of Henle extending into the medulla
renal fat pad	adipose tissue between the renal fascia and the renal capsule that provides protective cushioning to the kidney
renal hilum	recessed medial area of the kidney through which the renal artery, renal vein, ureters, lymphatics, and nerves pass
renal papillae	medullary area of the renal pyramids where collecting ducts empty urine into the minor calyces
renal pyramids	six to eight cone-shaped tissues in the medulla of the kidney containing collecting ducts and the loops of Henle of juxtamedullary nephrons
vasa recta	branches of the efferent arterioles that parallel the course of the loops of Henle and are continuous with the peritubular capillaries; with the glomerulus, form a portal system
angiotensin-converting enzyme (ACE)	enzyme produced by the lungs that catalyzes the reaction of inactive angiotensin I into active angiotensin II
angiotensin I	protein produced by the enzymatic action of renin on angiotensinogen; inactive precursor of angiotensin II
angiotensin II	protein produced by the enzymatic action of ACE on inactive angiotensin I; actively causes vasoconstriction and stimulates aldosterone release by the adrenal cortex
angiotensinogen	inactive protein in the circulation produced by the liver; precursor of angiotensin I; must be modified by the enzymes renin and ACE to be activated
aquaporin	protein-forming water channels through the lipid bilayer of the cell; allows water to cross; activation in the collecting ducts is under the control of ADH
brush border	formed by microvilli on the surface of certain cuboidal cells; in the kidney it is found in the PCT; increases surface area for absorption in the kidney
fenestrations	small windows through a cell, allowing rapid filtration based on size; formed in such a way as to allow substances to cross through a cell without mixing with cell contents
filtration slits	formed by pedicels of podocytes; substances filter between the pedicels based on size
forming urine	filtrate undergoing modifications through secretion and reabsorption before true urine is produced
juxtaglomerular apparatus (JGA)	located at the juncture of the DCT and the afferent and efferent arterioles of the glomerulus; plays a role in the regulation of renal blood flow and GFR
juxtaglomerular cell	modified smooth muscle cells of the afferent arteriole; secretes renin in response to a drop in blood pressure
macula densa	cells found in the part of the DCT forming the JGA; sense Na⁺ concentration in the forming urine
mesangial	contractile cells found in the glomerulus; can contract or relax to regulate filtration rate
pedicels	finger-like projections of podocytes surrounding glomerular capillaries; interdigitate to form a filtration membrane
podocytes	cells forming finger-like processes; form the visceral layer of Bowman’s capsule; pedicels of the podocytes interdigitate to form a filtration membrane
renin	enzyme produced by juxtaglomerular cells in response to decreased blood pressure or sympathetic nervous activity; catalyzes the conversion of angiotensinogen into angiotensin I
anatomical sphincter	smooth or skeletal muscle surrounding the lumen of a vessel or hollow organ that can restrict flow when contracted
detrusor muscle	smooth muscle in the bladder wall; fibers run in all directions to reduce the size of the organ when emptying it of urine
external urinary sphincter	skeletal muscle; must be relaxed consciously to void urine
internal urinary sphincter	smooth muscle at the juncture of the bladder and urethra; relaxes as the bladder fills to allow urine into the urethra
incontinence	loss of ability to control micturition
micturition	also called urination or voiding
physiological sphincter	sphincter consisting of circular smooth muscle indistinguishable from adjacent muscle but possessing differential innervations, permitting its function as a sphincter; structurally weak
retroperitoneal	outside the peritoneal cavity; in the case of the kidney and ureters, between the parietal peritoneum and the abdominal wall
sacral micturition center	group of neurons in the sacral region of the spinal cord that controls urination; acts reflexively unless its action is modified by higher brain centers to allow voluntary urination
trigone	area at the base of the bladder marked by the two ureters in the posterior–lateral aspect and the urethral orifice in the anterior aspect oriented like points on a triangle
urethra	transports urine from the bladder to the outside environment
anuria	absence of urine produced; production of 50 mL or less per day
leukocyte esterase	enzyme produced by leukocytes that can be detected in the urine and that serves as an indirect indicator of urinary tract infection
oliguria	below normal urine production of 400–500 mL/day
polyuria	urine production in excess of 2.5 L/day; may be caused by diabetes insipidus, diabetes mellitus, or excessive use of diuretics
specific gravity	weight of a liquid compared to pure water, which has a specific gravity of 1.0; any solute added to water will increase its specific gravity
urinalysis	analysis of urine to diagnose disease
urochrome	heme-derived pigment that imparts the typical yellow color of urine
blood–testis barrier	tight junctions between Sertoli cells that prevent bloodborne pathogens from gaining access to later stages of spermatogenesis and prevent the potential for an autoimmune reaction to haploid sperm
bulbourethral glands	(also, Cowper’s glands) glands that secrete a lubricating mucus that cleans and lubricates the urethra prior to and during ejaculation
corpus cavernosum	either of two columns of erectile tissue in the penis that fill with blood during an erection
corpus spongiosum	(plural = corpora cavernosa) column of erectile tissue in the penis that fills with blood during an erection and surrounds the penile urethra on the ventral portion of the penis
ductus deferens	(also, vas deferens) duct that transports sperm from the epididymis through the spermatic cord and into the ejaculatory duct; also referred as the vas deferens
ejaculatory duct	duct that connects the ampulla of the ductus deferens with the duct of the seminal vesicle at the prostatic urethra
epididymis	(plural = epididymides) coiled tubular structure in which sperm start to mature and are stored until ejaculation
gamete	haploid reproductive cell that contributes genetic material to form an offspring
glans penis	bulbous end of the penis that contains a large number of nerve endings
gonadotropin-releasing hormone (GnRH)	hormone released by the hypothalamus that regulates the production of follicle-stimulating hormone and luteinizing hormone from the pituitary gland
gonads	reproductive organs (testes in men and ovaries in women) that produce gametes and reproductive hormones
inguinal canal	opening in abdominal wall that connects the testes to the abdominal cavity
Leydig cells	cells between the seminiferous tubules of the testes that produce testosterone; a type of interstitial cell
penis	male organ of copulation
prepuce	(also, foreskin) flap of skin that forms a collar around, and thus protects and lubricates, the glans penis; also referred as the foreskin
prostate gland	doughnut-shaped gland at the base of the bladder surrounding the urethra and contributing fluid to semen during ejaculation
scrotum	external pouch of skin and muscle that houses the testes
semen	ejaculatory fluid composed of sperm and secretions from the seminal vesicles, prostate, and bulbourethral glands
seminal vesicle	gland that produces seminal fluid, which contributes to semen
seminiferous tubules	tube structures within the testes where spermatogenesis occurs
Sertoli cells	cells that support germ cells through the process of spermatogenesis; a type of sustentacular cell
sperm	(also, spermatozoon) male gamete
spermatic cord	bundle of nerves and blood vessels that supplies the testes; contains ductus deferens
spermatid	immature sperm cells produced by meiosis II of secondary spermatocytes
spermatocyte	cell that results from the division of spermatogonium and undergoes meiosis I and meiosis II to form spermatids
spermatogenesis	formation of new sperm, occurs in the seminiferous tubules of the testes
spermatogonia	(singular = spermatogonium) diploid precursor cells that become sperm
spermiogenesis	transformation of spermatids to spermatozoa during spermatogenesis
testes	(singular = testis) male gonads
alveoli	(of the breast) milk-secreting cells in the mammary gland
ampulla	(of the uterine tube) middle portion of the uterine tube in which fertilization often occurs
antrum	fluid-filled chamber that characterizes a mature tertiary (antral) follicle
areola	highly pigmented, circular area surrounding the raised nipple and containing areolar glands that secrete fluid important for lubrication during suckling
Bartholin’s glands	(also, greater vestibular glands) glands that produce a thick mucus that maintains moisture in the vulva area; also referred to as the greater vestibular glands
body of uterus	middle section of the uterus
broad ligament	wide ligament that supports the uterus by attaching laterally to both sides of the uterus and pelvic wall
cervix	elongate inferior end of the uterus where it connects to the vagina
clitoris	(also, glans clitoris) nerve-rich area of the vulva that contributes to sexual sensation during intercourse
corpus albicans	nonfunctional structure remaining in the ovarian stroma following structural and functional regression of the corpus luteum
corpus luteum	transformed follicle after ovulation that secretes progesterone
endometrium	inner lining of the uterus, part of which builds up during the secretory phase of the menstrual cycle and then sheds with menses
fimbriae	fingerlike projections on the distal uterine tubes
follicle	ovarian structure of one oocyte and surrounding granulosa (and later theca) cells
folliculogenesis	development of ovarian follicles from primordial to tertiary under the stimulation of gonadotropins
fundus	(of the uterus) domed portion of the uterus that is superior to the uterine tubes
granulosa cells	supportive cells in the ovarian follicle that produce estrogen
hymen	membrane that covers part of the opening of the vagina
infundibulum	(of the uterine tube) wide, distal portion of the uterine tube terminating in fimbriae
isthmus	narrow, medial portion of the uterine tube that joins the uterus
labia majora	hair-covered folds of skin located behind the mons pubis
labia minora	thin, pigmented, hairless flaps of skin located medial and deep to the labia majora
lactiferous ducts	ducts that connect the mammary glands to the nipple and allow for the transport of milk
lactiferous sinus	area of milk collection between alveoli and lactiferous duct
mammary glands	glands inside the breast that secrete milk
menarche	first menstruation in a pubertal female
menses	shedding of the inner portion of the endometrium out though the vagina; also referred to as menstruation
menses phase	phase of the menstrual cycle in which the endometrial lining is shed
menstrual cycle	approximately 28-day cycle of changes in the uterus consisting of a menses phase, a proliferative phase, and a secretory phase
mons pubis	mound of fatty tissue located at the front of the vulva
myometrium	smooth muscle layer of uterus that allows for uterine contractions during labor and expulsion of menstrual blood
oocyte	cell that results from the division of the oogonium and undergoes meiosis I at the LH surge and meiosis II at fertilization to become a haploid ovum
oogenesis	process by which oogonia divide by mitosis to primary oocytes, which undergo meiosis to produce the secondary oocyte and, upon fertilization, the ovum
oogonia	ovarian stem cells that undergo mitosis during female fetal development to form primary oocytes
ovarian cycle	approximately 28-day cycle of changes in the ovary consisting of a follicular phase and a luteal phase
ovaries	female gonads that produce oocytes and sex steroid hormones (notably estrogen and progesterone)
ovulation	release of a secondary oocyte and associated granulosa cells from an ovary
ovum	haploid female gamete resulting from completion of meiosis II at fertilization
perimetrium	outer epithelial layer of uterine wall
polar body	smaller cell produced during the process of meiosis in oogenesis
primary follicles	ovarian follicles with a primary oocyte and one layer of cuboidal granulosa cells
primordial follicles	least developed ovarian follicles that consist of a single oocyte and a single layer of flat (squamous) granulosa cells
proliferative phase	phase of the menstrual cycle in which the endometrium proliferates
rugae	(of the vagina) folds of skin in the vagina that allow it to stretch during intercourse and childbirth
secondary follicles	ovarian follicles with a primary oocyte and multiple layers of granulosa cells
secretory phase	phase of the menstrual cycle in which the endometrium secretes a nutrient-rich fluid in preparation for implantation of an embryo
suspensory ligaments	bands of connective tissue that suspend the breast onto the chest wall by attachment to the overlying dermis
tertiary follicles	(also, antral follicles) ovarian follicles with a primary or secondary oocyte, multiple layers of granulosa cells, and a fully formed antrum
theca cells	estrogen-producing cells in a maturing ovarian follicle
uterine tubes	(also, fallopian tubes or oviducts) ducts that facilitate transport of an ovulated oocyte to the uterus
uterus	muscular hollow organ in which a fertilized egg develops into a fetus
vagina	tunnel-like organ that provides access to the uterus for the insertion of semen and from the uterus for the birth of a baby
vulva	external female genitalia
Müllerian duct	duct system present in the embryo that will eventually form the internal female reproductive structures
puberty	life stage during which a male or female adolescent becomes anatomically and physiologically capable of reproduction
secondary sex characteristics	physical characteristics that are influenced by sex steroid hormones and have supporting roles in reproductive function
Wolffian duct	duct system present in the embryo that will eventually form the internal male reproductive structures

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