| A | B |
|---|
| central nervous system | consists of brain and spinal cord |
| peripheral nervous system | nerves and sense organs |
| divisions of the peripheral nervous system | autonomic and somatic nervous systems |
| two types of cells in the nervous system | neurons and glia |
| Cells that conduct impulses | neurons |
| Cells that support neurons | glia |
| main part of neuron | cell body |
| branching projections that carry impulses toward cell body | dendrites |
| long structure that carries impulses away from cell body | axon |
| three types of neurons | sensory neurons, interneurons, motor neurons |
| three types of glia | astrocytes, microglia, oligodendrocytes |
| transmits impulses to spinal cord and brain | sensory neuron |
| transmits impulses away from spinal cord and brain to muscles and glands | motor neuron |
| transmits impulses from sensory neurons to motor neurons | interneuron |
| white, fatty substance that surrounds axons in PNS | myelin |
| cells that form myelin | Schwann cells |
| indentations between adjacent Schwann cells | Nodes of Ranvier |
| cell membrane of a Schwann cell | neurilemma |
| star-shaped glial cells that hold neurons close to blood vessels | astrocytes |
| glia that eat microbes by phagocytosis | microglia |
| a bundle of myelinated axons | nerve |
| this consists of myelinated axons only | white matter |
| this consists of unmyelinated axons, cell bodies, and dendrites | gray matter |
| thin layer of fibrous tissue around an axon | endoneurium |
| thin layer of fibrous tissue around a fascicle | perineurium |
| a group of wrapped axons within a nerve | fascicle |
| tough, fibrous sheath covering a whole nerve | epineurium |
| route traveled by a nerve impulse | neuron pathway |
| path of a reflex arc | receptor, sensory neuron, interneuron, motor neuron, effector |
| a self-propagating wave of electrical disturbance on the surface of neuron | nervous impulse |
| a change in a neuron's environment | stimulus |
| examples of stimuli | chemical change, change in pressure, change in temperature |
| excess of Na+ ions outside neuron | "resting" neuron |
| Na+ ions rush into neuron, producing temporary negative charge outside | chemical "disturbance" that forms the nerve impulse |
| nerve impulse "jumps" across myelin, from one Node of Ranvier to the next | saltatory conduction |
| place where impulses transmitted from one neuron (presynaptic neuron) to the next (postsynaptic neuron) | synapse |
| tiny bulge at end of a presynaptic neuron's axon | synaptic knob |
| space between synaptic knob and cell membrane of postsynaptic neuron | synaptic cleft |
| chemicals that carry impulse across synaptic cleft | neurotransmitters |
| neurotransmitter produced by motor neurons | acetylcholine |
| neurotransmitters that play a role in sleep, mood, pleasure recognition | catecholamines |
| neurotransmitters that inhibit pain impulses | endorphins |
