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a nerve cell; the basic building block of the nervous system.


the portion of the vertebrate nervous system consisting of the brain and spinal cord


subdivision of the nervous system that brings information to the cns

autonomic nerves

serves the internal organs of the body

nerve impulse

message that travels from the dendrites of a neuron to the axon


long nerve fiber that conducts away from the cell body of the neuron


the branching extensions of a neuron that receives messages and conducts impulses toward the cell body

Schwann cell

large nucleated cells that form myelin around the axons of neurons


the space between two neurons through which neurotransmiters travel


receives information about changes in the enviroment (stimuli)


muscles or glands that respond to impulses


something that causes a response

cell body

contains major concentration of the cytoplasm and the nucleus of the neuron


an electrically-insulating phospholipid (fat) layer that surrounds the axons of many neurons


A relatively simple, involuntary response to a stimulus.

resting potential

the potential difference between the two sides of the membrane of a nerve cell when the cell is not conducting an impulse

action potential

change in electrical potential that occurs between the inside and outside of a nerve or muscle fiber when it is stimulated

refractory period

the time after a neuron fires during which a stimulus will not evoke a response

saltatory conduction

transmission of an impulse by jumping


a chemical messenger that travels across the synapse from one neuron to the next and influences whether a neuron will generate an action potential(impulse)

spinal cord

part of central nervous system, links brain to rest of body


natural neurotransmitters linked to pain control

autonomic nervous system

The part of the nervous system that controls involuntary action and responses.

Parkinson's Disease

a progressive disease that destroys brain cells and is identified by muscular tremors, slowing of movement, and partial facial paralysis

Alzheimer's Disease

a disease that results in the progressive loss of an individual's memory and mental capacity.


"Lou Gherig's Disease" - progressive neurological disease in which the motor neurons degenerate to the point of total loss of motor function. The intelligence, memory, and personality is unaffected.

Multiple Sclerosis

disorder in which myelin is destroyed causing loss of motor activity


a type of glia; produce myelin sheath around nerve fibers in cns


main body of a neuron

nodes of Ranvier

gaps between Schwann cells


glia that resemble epithelial cells; found in the brain and spinal cord

Nissl bodies

organelles that provide protein molecules needed for transmission of nerve signals from one neuron to another

afferent impulse

impulse traveling toward the cns


tough fibrous sheath that covers the whole nerve

axon hillock

portion of the cell body from which the axon extends


an a three-neuron reflex arc, nerve cell that conducts impulses from a sensory neuron to a motor neuron


connective tissue that encircles a bundle of nerve fibers with a nerve

efferent neuron

neuron that transmits nerve impulses away from the cns to muscles or glands


one of the main two types of cells that compose the nervous system; support the function of the neurons

reflex arc

impulse conduction route to and from the cns; smallest portion of nervous system that can receive a stimulus and generate a response


thin wrapping of fibrous connective tissue that surrounds each axon in a nerve


star shaped glia

membrane potential

difference in electrical charge between inside and outside of the plasma membrane


one of the five types of glia; found in the cns; act in defense of other nerve cells

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