Monday, September 29, 2008

Phases of action potential of cardiac muscle

phase 0

initial rapid depolarization and the overshoot

due to opening of voltage-gated Na+ channels

phase 1

initial rapid repolarization

due to closure of Na+ channels & also opening of K+ channels

phase 2


due to a slower but prolonged opening of voltage-gated Ca2+ channels.

phase 3 to phase 4

Final repolarization to the resting membrane potential

due to closure of the Ca2+ channels and K+ efflux through various types of K+ channels.

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