Med Terms Chapter 12 (Nervous System)

cephal/o

head (combining form)

cerebell/o

cerebellum (combining form)

cerebr/o

cerebrum (combining form)

encephal/o

brain (combining form)

gli/o

glue (combining form)

medull/o

medulla oblongata (combining form)

mening/o

meninges (combining form)

meningi/o

meninges (combining form)

myel/o

spinal cord (combining form)

neur/o

nerve (combining form)

phas/o

speech (combining form)

poli/o

gray matter (combining form)

pont/o

pons (combining form)

radicul/o

nerve root (combining form)

thalam/o

thalamus (combining form)

thec/o

sheath (meninges) (combining form)

ventricul/o

brain ventricle (combining form)

-algesia

pain, sensitivity

-esthesia

feeling, sensation

-paresis

weakness

-phasia

speech

-plegia

paralysis

-taxia

muscle coordination

sensory receptors

nerve fibers located directly under the skin surface; detect temperature, pain, touch, and pressure; messages for these sensations are conveyed to the brain and spinal cord from nerve endings in the skin

muscles

bundles of parallel muscle tissue fibers

glands

organs of the body that release secretions

central nervous system (CNS)

consists of the brain and spinal cord

peripheral nervous system (PNS)

contains the cranial and spinal nerves

brain

organ that coordinates most body activities; center of all thought, memory, judgement, and emotion

spinal cord

provides a pathway for impulses traveling to and from the brain; column of nerve fibers that extends from the medulla oblongata to the level of the 2nd lumbar vertebra

nerves

structures in the nervous system that conduct electrical impulses from the brain and spinal cord to muscles and other organs

cranial nerves

nerves that arise from the brain

spinal nerves

nerves that arise from the spinal cord

neurons

individual nerve cells; group together to form nerves and other nervous tissue

neuroglial cells

cells that perform support functions for neurons

dendrites

highly branched projections on neurons that receive impulses

nerve cell body

part of the neuron that contains the nucleus and many other organelles

axon

projection from the nerve cell body that conducts the electrical impulse toward its destination

synapse

point at which the axon of one neuron meets the dendrite of the next neuron

synaptic cleft

gap between two neurons

neurotransmitter

chemical messenger that helps electrical impulses pass the synpaptic cleft

myelin

fatty substance that acts as insulation for many axons so that they conduct electrical impulses faster

gray matter

tissue within the CNS; consists of unsheathed nerve cell bodies and dendrites

white matter

tissue in the CNS; consists of myelinated nerve fibers

myelinated

nerve fibers covered with a layer of myelin

tracts

bundles of nerve fibers interconnecting different parts of the CNS

meninges

three membranes that encase and protect the CNS

cerebrum

largest section of the brain; located in upper portion of the brain; area that processes thoughts, judgement, memory, problem solving, and language

cerebellum

2nd largest portion of the brain, located beneath the posterior portion of the cerebrum; aids in coordinating voluntary body movements and maintaining balance and equilibrium; attached to the brain stem by the pons; refines muscular movement that is initiated in the cerebrum

diencephalon

portion of the brain that contains two of the most critical areas of the brain, the thalamus and hypothalamus

brain stem

area of the brain with three components: medulla oblongata, pons, and midbrain; pathway for impulses to be conducted between the brain and spinal cord; contains centers that control respiration, heart rate, and blood pressure; 12 pairs of cranial nerves begin here

cerebral cortex

outer layer of the cerebrum composed of folds of gray matter

gyri

convolutions (elevated portions) of the cerebrum

sulci

fissures that separate the gyri of the cerebrum

cerebral hemispheres

left and right halves of the cerebrum

frontal lobe

most anterior portion of the cerebrum; controls motor function, personality, and speech

parietal lobe

most superior portion of the cerebrum; receives and interprets nerve impulses from sensory receptors and interprets language

occipital lobe

most posterior portion of the cerebrum; controls vision

temporal lobe

left and right lateral portion of the cerebrum; controls hearing and smell

thalamus

portion of the diencephalon; composed of gray matter and acts as a center for relaying impulses from the eyes, ears, and skin to the cerebrum; also controls pain perception

hypothalamus

portion of the diencephalon that lies just below the thalamus; controls body temperature, appetite, sleep, sexual desire, and emotions such as fear; also regulates release of hormones from the pituitary gland and regulates parasympathetic and sympathetic nervous systems

midbrain

part of brain stem that acts as a pathway for impulses to be conducted between the brain and spinal cord

pons

part of the brain stem that connects the cerebellum to the rest of the brain

medulla oblongata

most inferior positioned portion of the brain; connects brain to spinal cord; contains centers that control respiration, heart rate, temperature, and blood pressure; also the site where nerve tracts cross from one side of the brain to control functions and movement on the other side of the body

ventricles

four interconnected cavities within the brain: one in each cerebral hemisphere, one in the thalamus, and one in front of the cerebellum

cerebrospinal fluid (CSF)

watery, clear fluid that provides protection from shock or sudden motion to the brain and spinal cord; located in brain ventricles and central canal

vertebral column

column of 26 vertebrae that forms the backbone and protects the spinal cord; divided into 5 sections: cervical, thoracic, and lumbar vertebrae, sacrum, and coccyx

spinal cavity (vertebral canal)

continuous canal for the spinal cord

central canal

canal that extends down the length of the spinal cord; contains cerebrospinal fluid

ascending tracts

nerve tracts carrying sensory information up the spinal cord to the brain

descending tracts

nerve tracts carrying motor signals down the spinal cord to the muscles

dura mater

term meaning "tough mother"; the fibrous outermost meninges layer that forms a tough protective layer

subdural space

actual space between the dura mater and arachnoid meninges layers

arachnoid layer

term meaning "spiderlike"; the thin, delicate meninges layer attached to the pia mater by weblike filaments

subarachnoid space

space between the arachnoid layer and pia mater meninges layers; contains cerebrospinal fluid that cushions the brain from the outside

pia mater

term meaning "soft mother"; innermost meninges layer that is applied directly to the surface of the brain and spinal cord

nerve root

point where a spinal or cranial nerve is attached to the CNS

afferent neurons (sensory neurons)

neurons that carry sensory information from a sensory receptor to the CNS

efferent neurons (motor neurons)

neurons that carry activity instructions from the CNS to muscles or glands out in the body

ganglion

knotlike mass of nerve tissue located outside the brain and spinal cord

autonomic nervous system (ANS)

consists of nerves to the internal organs that function involuntarily; regulates functions of glands (especially salivary, gastric, and sweat glands), adrenal medulla, heart, and smooth muscle tissue; divided into two parts; sympathetic and parasympathetic

somatic nerves

nerves that serve the skin and skeletal muscles and are mainly involved with the conscious and voluntary activities of the body

sympathetic branch

branch of autonomic nervous system; stimulates the body in times of stress and crisis by increasing heart rate, dilating airways to allow for more oxygen, increasing blood pressure, inhibiting digestion, and stimulating production of adrenaline during a crisis

parasympathetic branch

branch of autonomic nervous system; serves as a counterbalance for sympathetic nerves; therefore, it causes heart rate to slow down, decreases blood pressure, constricts eye pupils, and increases digestion

cephalalgia

head pain (headache)

cerebellar

pertaining to the cerebellum

cerebellitis

cerebellum inflammation

cerebral

pertaining to the cerebrum

cerebrospinal

pertaining to the cerebrum and spine

electroencephalogram (EEG)

record of brain's electricity

encephalitis

brain inflammation

meningioma

meninges tumor

meningeal

pertaining to the meninges

meningitis

meninges inflammation

myelogram

record of spinal cord

myelitis

spinal cord inflammation

neural

pertaining to nerves

neuralgia

nerve pain

neurectomy

removal of a nerve

neurologist

specialist in nerves