23.5: Key Terms

amyotrophic lateral sclerosis (ALS)

a progressive neurological disorder that affects motor neurons

anterior horn

gray-matter region of the spinal cord that contains multipolar motor neurons, sometimes referred to as the ventral horn

appendicular skeleton

consists of the limbs, which are attached to the axial skeleton

ascending tract

a column of nervous system fibers that carry sensory information up to the brain

aspiration

the process of food or other foreign particles entering the airway

autonomic nervous system (ANS)

component of the peripheral nervous system that regulates involuntary physiologic responses and includes the sympathetic and parasympathetic nervous system

axial skeleton

consists of 80 bones that form the head and trunk of the body

bone

hard, dense connective tissue that form most of the adult skeleton, the primary support structure of the body

brain

contained within the cranial cavity of the skull is the central organ of the nervous system responsible for controlling bodily functions, processing sensory information, and enabling cognitive processes such as learning and memory

brain stem

region of the adult brain that includes the midbrain, pons, and medulla oblongata, which develops from the mesencephalon, metencephalon, and myelencephalon of the embryonic brain

cardiac muscle

muscle specifically related to cardiac tissue

cartilage

type of connective tissue that provides structural support and flexibility and helps reduce friction during joint movement

cauda equina

a bundle of nerve roots located at the end of the spinal cord that resembles a horse’s tail

central nervous system (CNS)

the primary processing center of the body; includes the brain and spinal cord

cerebellum

an area of the brain largely responsible for comparing information from the cerebrum with sensory feedback from the periphery through the spinal cord

cerebral cortex

the outer gray matter covering the forebrain, marked by wrinkles and grooves known as gyri and sulci

cerebral hemisphere

one half of the bilaterally symmetrical cerebrum

cerebral palsy (CP)

an umbrella term for a group of disorders caused by damage to the brain during pregnancy, childbirth, or in early infancy that affect the ability to move and stay balanced

cerebrum

the region of the brain responsible for higher neurological functions such as memory, emotion, consciousness, and voluntary muscle movement

Charcot-Marie-Tooth (CMT) disease

a progressive genetic neuromuscular disorder that affects the peripheral nerves, most often those of the arms, hands, legs, and feet

congenital myopathy

a genetic muscle deformity that is present from birth resulting in a lack of muscle tone and severe muscle weakness

connective tissue

cartilage, ligaments, and tendons that connect tissues and organs

corpus callosum

the large white matter structure that connects the cerebrum to the rest of the nervous system and provides the major pathway for communication between the right and left cerebral hemispheres

cranial nerve

one of twelve nerves connected to the brain that are responsible for sensory and motor functions of the head and neck

deep vein thrombosis (DVT)

the formation of a blood clot in the deep veins in the body, usually in the legs

descending tract

a column of nervous system fibers that carry motor commands from the brain

diencephalon

the region of the adult brain that retains its name from embryonic development and includes the thalamus and hypothalamus

diplopia

double vision

electromyography (EMG)

a diagnostic procedure involving small needles that record electrical activity in the muscles

excitability

the ability of muscle plasma membranes to change electrical states and send action potentials along the entire length of a membrane to cause contraction

gray matter

the butterfly-shaped structure consisting of neuronal cell bodies that is subdivided into regions called horns and is involved in processing information in the brain.

gyri

a wrinkle or fold formed by convolutions in the surface of the cerebral cortex

hypothalamus

a collection of nuclei that are largely involved in regulating homeostasis

hypotonia

decreased muscle tone

incontinence

the involuntary expulsion of urine or feces from the body

joint

a location where bones come into contact, allowing for movement

lateral horn

the 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

ligament

tough but flexible fibrous tissue that connects bones or holds joints together

longitudinal fissure

the separation of tissue in the cerebrum that divides the brain into two distinct halves (cerebral hemispheres)

medulla

the connection point between the brain stem and spinal cord

motor neuron

a nerve cell that receive signals from the brain and spinal cord to cause voluntary skeletal muscle movements and breathing

multiple sclerosis (MS)

a neurological disorder that causes immune system cells to attack myelin; subtypes of MS include relapsing-remitting, secondary-progressive, primary-progressive, and progressive-relapsing

muscle atrophy

the wasting and breakdown of muscle tissue

muscular dystrophy

a genetic muscular disorder that results in progressive muscle weakness

myasthenia gravis

an autoimmune disorder in which antibodies attack the neuromuscular junction of skeletal muscles, resulting in progressive muscle weakness (e.g., arms, hands, fingers, legs, neck) and fatigue

myelin

the protective coating on nerves

negative feedback

a mechanism that reverses a deviation from the set point

nerve conduction velocity (NCV) testing

a diagnostic procedure involving placement of electrodes over nerves to determine how fast nerve signals are sent to skeletal muscles

neuromuscular junction (NMJ)

the site where a motor neuron’s terminal meets the muscle fiber and responds to motor signals

paralysis

a complete loss of sensation and mobility

paraplegia

paralysis of the legs and portions of the trunk but not the arms

parasympathetic nervous system

the part of the ANS that results in involuntary “rest and digest” types of reactions

peripheral nervous system (PNS)

the portion of the nervous system located on the periphery of the central nervous system containing peripheral structures including ganglia and nerves

pons

the connection point between the medulla and the thalamus

posterior horn

the gray-matter region of the spinal cord in which sensory input arrives

ptosis

eyelid drooping

set point

the physiological value around which the normal range fluctuates

skeletal muscle

muscle that attaches to bone and creates intentional movement as it contracts and relaxes, causing the bones to move

skeletal system

the bones, joints, and other structures that allow for movement, form the body, make blood cells, and shield organs

smooth muscle

muscle in the walls of hollow organs such as the urinary bladder, uterus, stomach, and intestines

somatic nervous system

the part of the peripheral nervous system that controls voluntary movements of skeletal muscle

spinal cord

a long, thin, tube-shaped bundle of nerves that extends from the base of the brain through the vertebral column; contained within the vertebral cavity of the vertebral column

spinal cord injury

damage to the spinal cord, often as a result of trauma (e.g., a motor vehicle accident, a fall) or cancer

spinal nerve

one of thirty-one peripheral nerves connected to the spinal cord; each is named for the level of the spinal cord at which it emerges

sulci

grooves formed by convolutions in the surface of the cerebral cortex

sympathetic nervous system

the part of the ANS that causes involuntary reactions in the body to help combat a perceived threat resulting in “fight or flight” types of reactions

tendon

a tough connective tissue located on each side of a joint that controls joint movement

tetraplegia

paralysis from the neck down

thalamus

a collection of nuclei that relay information between the cerebral cortex and the brain stem, spinal cord, and periphery

tracheostomy

an opening in the trachea into which a tube is placed that allows for mechanical ventilation to be delivered

white matter

myelinated nerve fibers that facilitate communication between different regions of the brain