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10 Cards in this Set
- Front
- Back
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peripheral nervous system |
the portion of the nervous system that consists of nervous tissue structures that lie outside the brain and spina cord. Senses changes in the environment, sends information to the central nervous system and recieves information to CNS |
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central nervous system |
the portion of the nervois system that is composed of brian and spinal cord. Proccess information and makes decisions |
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dendrites |
extensions of the cell body (processes) that receive information |
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axon |
long process that conducts information to another cell (neuron, effector). Has electrical impulses away from cell body and is involved in signalling motor activity |
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Schwann call |
produce myelin around the single axon and help in neruon regenerationmaintain myelin sheath around a peripheral neuron |
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myelin sheath |
layed fatty covery that insulates axon, they speed the conduction of impulses |
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multipolar neuron |
have several dendrites and one axon. Found in brain and spinal cord |
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bipolar neuron |
have one dendrite and one axon. Found in the retina of eye, inner ear, and olfactory areas of brain |
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unipolar neuron |
have dendrites and axons fused into one proces. Most sensory neurons are unipolar |
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action potential |
electircal signal that propages along the membran of a neuron sodium and potassium channels open and close I sequence during phases 1. Resting state: the membrane is not permeable to na or k. excess positive ions are on the outside of membrane and excess negative ions are on inside. It is at -70mV 2. Depolarizing phase: following a stimulus NA+ channels open and NA+ enters the nerve fiber. If the fiber reaches the threshold a huge influx of na occurs and the membrane charges reverse. This triggers the action potential. +30 mV 3. Repolarizing phase: resets the membrane the membrane becomes impermeable to na + again and it becomes permeable to K+ -10mV 4. Repolarization continues: na and k ions are mopved back across membrane to help return the nerve fiber to resting at -70 |
