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Across 3. is the part of the peripheral nervous system [1] associated with the voluntary control of body movements via skeletal muscles. 5. a small cystic tumor (as on the back of the wrist) containing viscid fluid and connected either with a joint membrane or tendon sheath 12. are the cells which line the ventricles of the brain 16. a substance (as norepinephrine or acetylcholine) that transmits nerve impulses across a synapse 19. It is a component of a muscle fiber's muscle spindle which keeps track of how fast a muscle stretch changes (the velocity of the stretch). 21. carry nerve impulses away from the central nervous system to effectors such as muscles or glands (and also the ciliated cells of the inner ear). 24. The gaps (approximately 1 micrometer wide) formed between myelin sheath cells long the axons 26. glia consisting of small cells with few processes that are scattered throughout the central nervous system 27. a bodily organ (as a gland or muscle) that becomes active in response to stimulation

Down 1. the part of the nervous system that is outside the central nervous system and comprises the cranial nerves excepting the optic nerve, the spinal nerves, and the autonomic nervous system 2. the part of the nervous system which in vertebrates consists of the brain and spinal cord, to which sensory impulses are transmitted and from which motor impulses pass out, 4. a sensory nerve ending that responds to a stimulus in the internal or external environment of an organism. 6. the principal glia of the peripheral nervous system (PNS). 7. a part of the vertebrate nervous system that innervates smooth and cardiac muscle and glandular tissues and governs involuntary actions 8. the place at which a nervous impulse passes from one neuron to another 9. the supportive tissue of the nervous system, 10. the insulating covering that surrounds an axon with multiple spiral layers of myelin 11. a glial cell resembling an astrocyte but smaller with few and slender processes having few branches 13. the membrane potential of a cell that is not exhibiting the activity resulting from a stimulus 14. the membrane potential to which a membrane must be depolarized to initiate an action potential. 15. the nucleus-containing central part of a neuron exclusive of its axons and dendrites that is the major structural element of the gray matter of the brain and spinal cord 17. a star-shaped cell ; especially : any comparatively large much-branched glial cell 18. a momentary reversal in the potential difference across a plasma membrane (as of a nerve cell or muscle fiber) that occurs when a cell has been activated by a stimulus 20. any of the usually branching protoplasmic processes that conduct impulses toward the body of a nerve cell 22. any of the filamentous bands of nervous tissue that connect parts of the nervous system with the other organs 23. one of the cells that constitute nervous tissue, that have the property of transmitting and receiving nervous impulses 25. a usually long and single nerve-cell process that usually conducts impulses away from the cell body