Action_Potentials_10.3

Action_Potentials_10.3 - Action Potentials-large changes in...

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Action Potentials -large changes in membrane potential -rapid and high frequency -All of none event -Produced in excited cells -voltage-gated Na and K channels -opening = larg rapid Vm Events of an action potential: Action Potential (cont.) -Threshold potential -Vm (voltage) required to activate Na channels -Weak depolarizations= subthreshold potentials -stimulus then generated Na current Action potential amplitude: -Independent of stimulus….as long as stiumuls is above the threshold Practical applications: -Local anesthetics (don’t let action potential accure) -Blocks Na Channels 1) membrane at rest (-70mV) 2) local depolarization reaches threshold; voltage-gated Na channels open 3)Na influx; cell depolarizes more 4) Na channels inactivated; K channels open 5) K outflux, cell repolarization; Na channels close 6) cell hyperpolarizes since K slow to close 7) K channels close; neg. feedback return to rest
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How Action Potentials Move : (cup to balcony) -Adjacent sections of membrane -no movement of single action potential
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This note was uploaded on 04/22/2008 for the course EEOB 232 taught by Professor Bronson during the Spring '07 term at Ohio State.

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Action_Potentials_10.3 - Action Potentials-large changes in...

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