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Check

Across: 1. The sign of the potential difference across a nerve cell membrane expressed as inside versus outside (8) 4. A group of nerve axons running together form this (5) 7. Abbreviation for the period during which a neuron is completely unable to produce a neural response (3) 9. The glial cells in the periphery that provide a fatty insulation to some nerve axons (7,5) 10. The white fatty wrapping that reduces current leakage across a nerve membrane (6) 12. The site on the nerve where input is usually integrated (4,7) 16. The point of functional contact between a nerve and another cell (7) 17. One of the two factors used by channels to be selective as to what ion will pass through (4) 18. The class of neurons that control muscles and glands (5) 20. The class of proteins that allow ion movement but only under contolled conditions (5) 21. This equation allows calculation of the charge difference to balance off the concentration gradient for a permeating ion across a membrane (6) 22. Abbreviation for the 6-8 msec period during which a neuron can produce a second neural response but only for much stronger stimuli (3) 23. The region of the channel through which ions traverse (4) 24. The unmyelinated regions of a myelinated nerve where neural signals are regenerated (5)

Down: 2. The class of cells that make up 90% or so of the CNS (4) 3. The charge difference that balances off the concentration gradient for a permeating ion across a permeable membrane (11,9) 5. The term for the trigger level for an action potential (9) 6. The collections of nerve cell bodies in the peripheral nervous system (7) 8. The cyoplasmic extensions of a neuron where most inputs occur (9) 11. Invertebrates increase this to increase speed of transmission of information (4,8) 13. The set of neurons that transmit information between neurons (12) 14. A reduction in the number of nerve responses despite a sustained stimulus (10) 15. The axon branches through which neurons communicate with other cells (9) 16. A typical value for the difference in charge between the inside and outside of the neuron (7) 19. The parameter of neural signals that neurons vary to signal changes in stimulus intensity (9)