The Power Course

Repolarization is caused by which channels in ventricular muscles


1 ) Na channels
2 ) Cl channels
3 ) K channels
4 ) HCO3 channels


Action potential in Ventricular Myocardium

Resting membrane potential in ventricular myocardium is -90 mV. The action potential is divided into 5 phases starting from 0.

Phase 0

Rapid depolarization is due opening of Na channels

Phase 1

Initial rapid repolarization is due to the closure of Na channel and opening of K channels

Phase 2

Plateau phase is due to slow but the prolonged opening of voltage-gated Ca channels

Phase 3  and Phase 4

Phase 3 Late rapid repolarization and Phase 4 baseline is due to the closure of slow Ca channels and slow delayed increase K efflux via various K channels


K channels

Last Modified : 25-Dec-2019

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