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7 Cards in this Set
- Front
- Back
What would Vm look like for a local potential along an axon? Why does this happen?
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Would fade out over time and distance (not enough to depolarize cell and open Na+ channels; leak out of ion channels along the way)
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What motivation do ions have to move along an axon?
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Ionic repulsion
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Describe the path of ions when injected into an axon.
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Propel along bc of ionic repulsion, collect at membrane bc membrane acts as capacitor.
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Assume threshold is reached during depolarization of a neuron, describe the graph of an action potential using E values as reference points.
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Starts at Vm, Na+ channels open, depolarize toward E of Na+, Na+ channels close, K+ channels open, approach E of K+ (beneath initial Vrest), K+ channels close, Na+/K+ pump works back up to Vrest
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Why don't K+ channels open at same time as Na+ channels?
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K+ channels are delayed rectifier channels; open more slowly in response to depolarization
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What is the absolute refractory period? When does it occur?
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Na+ channels are inactivated and cannot be re-opened no matter what the stimulus; occurs under spike in action potential graph
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What is the relative refractory period? When does it occur?
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Have to stimulate harder to get an AP; occurs during Na+/K+ pump part of graph to get back up from hyperpolarization
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