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    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 T3 and 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
    ischemi