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12 Cards in this Set
- Front
- Back
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What are the functions of the two subunits of the voltage gated Na+ channels?
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-alpha is the main functional component
-beta contains regulatory sites |
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Does the voltage gated K+ or Na+ channel inactivate?
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-the Na+ channel
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What is a property of conductances in parallel?
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-they are additive
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What is the net charge movement exactly at threshold?
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-one Na+ ion enters for every K+ ion that leaves
-net charge is zero |
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What happens to the voltage gated K+ channels during an action potential?
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-they open strongly
-the resulting K+ efflux repolarizes the membrane to at least the normal resting potential |
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Absolute refractory period
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-after an action potential this is the period of time that no depolarization (regardless of size) can elicit a 2nd action potential
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Length Constant
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-the distance over which passive ionic current may flow from a voltage source within an axon
-thicker axons have longer constants |
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Where are the Na+ channels in a myelinated axon?
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-in the nodes of ranvier
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Spatial Summation
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-the process of combining currents from synapses at different locations in a neuron
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Time constant (t)
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-t=RC
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Temporal Summation
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-successive EPSPs or IPSPs can add together if they arrive at a rate close to 1/t
-larger t makes temporal summation more likely |
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Does the length or time constant have a greater effect on conduction velocity?
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-length constant
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