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17 Cards in this Set
- Front
- Back
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what two types of neurons are in the efferent peripheral nervous system?
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-autonomic neurons
-somatic neurons |
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what do they innervate?
-autonomic neurons -somatic neurons |
auto = cardiac/smooth muscle and glands.
somatic = skeletal muscle |
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what is a motor unit?
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an alpha motor neuron and the muscle cells it innervates.
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how many cells do motor units innervate?
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from 3 to 1700
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what do smaller motor units control?
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fine movement.
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where do alpha motor neurons originate?
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in the ventral horn of the spinal cord.
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what is different between a post-synaptic potential and a motor-end-plate potential?
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-PSPs can be excitatory OR inhibitory; are generally small.
-EPPs are generally LARGE and are ONLY excitatory. |
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How many EPPs are necessary to generate an action potential?
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only one
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if EPPs are always excitatory, how can they be inhibited?
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-By inhibiting the alpha motor neuron within the spinal cord.
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what in general are 5 effects of chemical agents and diseases on somatic movement?
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1. Botulism
2. Black Widow Spiders 3. Organophosphates and other 4. Curare 5. Myasthenia gravis |
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What is Botulism?
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disease caused by clostridium toxin; it blocks release of AcH and since the excitatory neuron can't reach EPPs, causes paralysis.
-not usually cause of death, but maybe respiratory failure |
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what is caused by a black widow spider?
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too MUCH acetylcholine release.
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what do organophosphates, nerve gas, herbicides/pesticides do to the nervous system?
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-block acetylchololinesterase so you get tremendous excition!
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what does Curare do?
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blocks the nictotinic AcH receptor and works as an anasthetic.
binds the receptor, without activatating. |
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what does is myasthenia gravis?
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automimune disease where Ab form to the Nicotinic receptors; causes muscle weakening and is treated by blocking AcHesterase.
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how does blocking AcHesterase treat myasthenia gravis?
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it allows AcH to stay in the synaptic space longer, so the chances of it binding a receptor are better.
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what 5 chemical agents cause tremendeous excitation of all cholineric receptors? how?
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-organophosphates
-nerve gas -sarin -herbicides/pesticides Blocks AcHesterase. |
