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Across 1. A gap in the myelin sheath of a nerve, between adjacent Schwann cells. 6. The electrical potential of a neuron or other excitable cell relative to its surroundings when at rest. 8. A short branched extension of a nerve cell, along which impulses received from other cells at synapses are transmitted to the cell body 12. a nerve fiber that carries impulses toward the muscles or glands 14. A junction between two nerve cells, consisting of a minute gap across which impulses pass by diffusion of a neurotransmitter 19. A specialized cell transmitting nerve impulses; a nerve cell. 23. any nerve that transmits impulses from the periphery toward the central nervous system 24. neuroglial tissue of mesodermal origin that can become phagocytic 26. The soma (pl. somata or somas), or perikaryon (pl. perikarya), or cyton, is the bulbous end of a neuron, containing the cell nucleus 27. The complex of nerve tissues that controls the activities of the body. In vertebrates it comprises the brain and spinal cord.

Down 2. The part of the nervous system responsible for control of the bodily functions not consciously directed, such as breathing 3. Consists of all of the nerves in the body, outside the CNS, that carry signals from the CNS to the muscles 4. An organ or cell that acts in response to a stimulus 5. n organ having nerve endings (in the skin or viscera or eye or ear or nose or mouth) that responds to stimulation 7. The somatic nervous system (SNS) is the part of the peripheral nervous system associated with the control of body movements 9. A structure containing a number of nerve cell bodies, typically linked by synapses, and often forming a swelling on a nerve fiber. 10. A whitish fiber or bundle of fibers that transmits impulses of sensation to the brain or spinal cord 11. A chemical substance that is released at the end of a nerve fiber by the arrival of a nerve impulse and causes the transfer 13. is the membrane potential to which a membrane must be depolarized to initiate an action potential 15. the electrical activity developed in a muscle or nerve cell during activity. 16. A star-shaped glial cell of the central nervous system. 17. neuroglial tissue of mesodermal origin that can become phagocytic. 18. a wrapping of myelin around certain nerve axons, serving as an electrical insulator that speeds nerve impulses to muscles and other effectors. 20. a cell of the peripheral nervous system that wraps around a nerve fiber, jelly-roll fashion, forming the myelin sheath. 21. sustentacular tissue that surrounds and supports neurons in the central nervous system; 22. a cell of the oligodendroglia. 25. The long threadlike part of a nerve cell along which impulses are conducted from the cell.