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9 Cards in this Set
- Front
- Back
normal neuromuscular junction
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action potential depolarizes motor neuron terminal, Ca2+ influx facilitates presynaptic release of ACh which binds to postsynaptic muscle membrane. End plate depolarization, electrical propagation, muscle contraction.
Acetylcholinesterase limits the action of ACh. |
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myasthenia gravis
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antibodies to acetylcholine receptor block receptor sites, increased receptor degradation and turnover, clinical weakness
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Lambert-Eaton myasthenic syndrome
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presumed immunologic attack on presynaptic calcium channels which impairs release of ACh, usually related to underlying cancer
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polio
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viral infection primarily of lower motor neurons
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spinal muscular atrophy
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infantile = Werdnig-Hoffman
childhood and adult = Kugelberg-Welander adult benign focal amyotrophy involves one limb, best prognosis all exhibit lower motor neuron signs |
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primary lateral sclerosis
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involves corticospinal tracts, upper motor neuron signs. no structural or metabolic cause known.
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progressive bulbar palsy
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involves brain stem motor nuclei
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pseudobulbar palsy
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involves corticobulbar tracts, upper motor neuron signs
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amyotrophic lateral sclerosis (ALS, Lou Gehrig disease)
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degeneration of corticospinal and corticobulbar tracts
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