L-04ActionPotential

L-04ActionPotential - Action Potential Review When...

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1/30/07 Action Potential Review: When Electrostatic gradient = concentration gradient, equilibrium Potassium is the most crucial ion to the RMP o Changing the extracellular K+ concentration changes the RMP The Action Potential o A rapid, transient change in voltage (depolarization) within the axon Initiated proximal to the soma Progresses all the way to the axon terminals o Ion channel A specialized protein molecule that permits specific ions to enter or leave the cell; specific for ion species o Voltage-dependent (or voltage-gated) ion channels An ion channel that opens or closes depending on the membrane potential, V m Subthreshold Stimulation o Stimulation that does not lead to an action potential (instead, called graded potential) o Changes in membrane voltage follow rules of passive current flow in the axon (cable properties: describe laws of current decay as length grows) Suprathrehold stimulation o Depolarization stimulus brings large enough change to start an action
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This note was uploaded on 04/09/2008 for the course PSYC 220 taught by Professor Brunges during the Spring '07 term at UVA.

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L-04ActionPotential - Action Potential Review When...

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