| A | B |
|---|
| dendrites | numerous. Receives information |
| axon | one per neuron. Sends information |
| axon terminals | at end of axon. Holds neurotransmitters |
| cell body | metabolic center of cell |
| centrioles | non-existent in neurons - neurons don't divide!! |
| Schwann cells | PNS supporting cells. Surround axon, help form myelin sheath |
| myelin | white, fatty, insulating covering |
| Nodes of Ranvier | spaces between Schwann cells |
| endoneurium | connective tissue covering of each neuron |
| perineurium | connective tissue covering of fascicle |
| fascicle | a group of neurons bundled together, surrounded by perineurium |
| epineurium | connective tissue covering on outside of nerve |
| sodium | enters cell to change polarization in order to conduct message |
| sensory neurons | carry message from receptors to CNS |
| motor neurons | carry message from CNS to destination (organ, muscle, gland) |
| associated neurons | link sensory and motor. Integrate information in CNS |
| irritability | ability to receive stimuli |
| conductivity | ability to send message |
| synaptic cleft | the space between two cells |
| synapse | the passage of a message across the synaptic cleft |
| central nervous system | brain and spinal cord |
| peripheral nervous system | nerves outside the brain and spinal cord |
| somatic | voluntary portion of PNS |
| autonomic | involuntary portion of PNS |
| parasympathetic | resting and digesting division of autonomic |
| sympathetic division | fight or flight division of autonomic |
| neuroglia | supporting cells in CNS - astrocytes, microglia, ependymal, oligodendrocytes |
| meninges | 3-layered protective membrane around CNS |
| dura mater | outermost layer of meninges - hard mother |
| arachnoid mater | middle layer of meninges |
| pia mater | innermost layer of meninges - little mother |
| subarachnoid space | space under the arachnoid layer that contains cerebrospinal fluid |
| cerebrospinal fluid | CSF - watery broth formed from blood plasma. Provides watery cushion to CNS |
| spinal cord | approx. 17 inches long. ends around L2 |
| lumbar puncture | test where needle is inserted into spine to draw CSF. usually done around L3 |
| cauda equina | fray of nerves at end of spinal cord. Means Horse's tail. |
| neural gating theory | fibers that carry pain message are blocked by fibers that carry light touch message |
