Term
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Definition
Resting: m- (Na) and n-gates (K) closed; h-gate open
Depolarizing: m- and h-gate open; n-gate closed
Repolarizing: h-gate closed; m- and n-gate open
Undershoot: m- and h-gate closed; m-gate open |
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Term
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Definition
| causes sustained depolarization and the h-gate to close--no AP |
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Term
| voltage-activated Na and Ca similarities |
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Definition
| 4 repeating domains with 6 subunits each; basic domain that opens/closes pore based on internal charge (closed at rest and open as cell depolarizes); Ca has alpha 2, beta, gamma, and delta additions |
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Term
| Single channel currents and membrane excitability |
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Definition
Na-current is inward and recorded as negative
K-current is outward and recorded as positive
TTX blocks Na channel
TEA blocks K channel |
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Term
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Definition
| the amount of time it takes an injection of current to change the membrane potential to 63% of its final value; high resistance (few ion channels) and high capacitance (ability to absorb charge) lead to a long time constant = slower conduction velocity; nodes of ranvier decrease resistance; myelin reduces capacitance |
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Term
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Definition
| the distance from the source of current injection what the potential has fallen to 63% of its initial value; the longer the length constant the faster the conduction velocity |
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