Anatomy Ch 9 Sect. 1

Front 1

neuron

Back 1

a nerve cell

Front 2

neuroglial cell

Back 2

specialized cells of the nervous system that produce myelin, communicate between cells, and maintain ionic balance

Front 3

myelin

Back 3

fatty material that forms a sheathlike covering around some axons

Front 4

astrocytes

Back 4

a type of neuroglialcell that connects neurons to blood vessels

Front 5

ganglia

Back 5

sensory fibers in cranial nerves have neuron cell bodies outside the brain (usually in groups)

Front 6

bipolar neuron

Back 6

neurons with specialized parts of the eyes, ears, and nose; two processes one from each cell body; strucuturally similar one axon one dendrite

Front 7

synapse

Back 7

functional connection between the axon of a neuron and the dendrite or cell body of another neuron or the membrane of another cell type

Front 8

mixed nerve

Back 8

nerve that includes both sensory and motor neuron fibers

Front 9

nerve impulse

Back 9

the electrochemical process of depolarization and repolarization along an axon

Front 10

central nervous system (CNS)

Back 10

the brain and spinal cord

Front 11

somatic nervous system

Back 11

motor pathways of the peripheral nervous system that lead to the skin and skeletal muscles

Front 12

ependymal cell

Back 12

cell membrane composed of neuroglial cells that lines the ventricles of the brain

Front 13

nodes of Ranvier

Back 13

narrow gaps between Schwann cells

Front 14

multipolar neuron

Back 14

many processes, only one process of each is an axon; the rest are dendrites. most neurons whose cells bodies lie within the brain or spinal cord are multipolar

Front 15

threshold potential

Back 15

once summation is reached this may be reached; lots of subthreshold potential changes must combine to reach threshold and once threshold is reached, action potential occurs

Front 16

afferent fibers

Back 16

same as sensory neuron

Front 17

reflex arc

Back 17

nerve pathway, consisting of a sensory neuron, interneuron, and motor neuron, this forms structural and functional bases for a reflex

Front 18

dendrite

Back 18

process of a neuron that receives input from other neurons

Front 19

peripheral nervous system (PNS)

Back 19

the portions of the nervous system outside the central nervous system

Front 20

autonamic nevous system

Back 20

portion of nervous system that controls the viscera

Front 21

schwann cell

Back 21

type of neuroglial cell that surrounds an axon of a peripheral neuron, forms the neurilemmal sheath and myelin.

Front 22

sensory neuron

Back 22

neuron that transmits an impulse from a receptor to the central nervous system

Front 23

unipolar neuron

Back 23

single process extending from cell body, short distance from cell body, divides into two branches-function as single axon, one branch dealt with as dendrites, other branch enters spinal cord or brain.

Front 24

excitatory

Back 24

neurotransmitters that increase postsynaptic membrane permeability to sodium ions bring the membrane closer to threshold and may trigger nerve impulses

Front 25

efferent fibers

Back 25

same as motor neuron

Front 26

reflex

Back 26

rapid, autonamic response to a stimulus

Front 27

axon

Back 27

nerve fiber, conducts a nerve impulse away from neuron cell body

Front 28

sensory receptor

Back 28

specialized structure associated with the peripheral end of a sensory neuron specific to detecting a particular sensation and triggering a nerve impulse to the central nervous system

Front 29

oligodendrocytes

Back 29

type of neroglial cell that forms myelin

Front 30

neurofibrils

Back 30

fine, cytoplasmic thread that extends from the cell body into the process of a neuron

Front 31

interneurons

Back 31

a neuron between a sensory and motor neuron

Front 32

resting potential

Back 32

the difference in electrical charge between the inside and outside of an undisturbed nerve cell in the membrane

Front 33

inhibatory

Back 33

other neurotransmitters make it less likely that threshold will be reached, lessens the chance that a nerve impulse will occur

Front 34

sensory nerves

Back 34

nerve composed of sensory never fibers

Front 35

nerve

Back 35

bundle of axons in the peripheral nevous system

Front 36

effectors

Back 36

muscle or gland that effects change in the body

Front 37

microglial cell

Back 37

neuroglial cell that supports neurons and phagocytizes

Front 38

neurilemma

Back 38

portion of schwann cell that contains most of the cytoplasm and the nuclei remain on the outside the myelin sheath

Front 39

motor neuron

Back 39

neuron that transmits impulses from the central nervous system to an effector

Front 40

action potential

Back 40

the sequence of electrical changes that occurs in a portion of a nerve cell membrane that is exposed to a stimulus that exceeds the membrane's threshold

Front 41

motor nerves

Back 41

nerve that consist of motor neuron axons