MEDICAL PHYSIOLOGY

Detailed explanation-1: -The subsequent return to resting potential, repolarization, is mediated by the opening of potassium ion channels. To reestablish the appropriate balance of ions, an ATP-driven pump (Na/K-ATPase) induces movement of sodium ions out of the cell and potassium ions into the cell.

Detailed explanation-2: -At the peak action potential, K+ channels open and K+ begins to leave the cell. At the same time, Na+ channels close. The membrane becomes hyperpolarized as K+ ions continue to leave the cell.

Detailed explanation-3: -The opening of these potassium channels is voltage dependent and allows K+ to leave the cell, thereby restoring the resting potential of the axonal membrane.

Detailed explanation-4: -Repolarization is caused by the closing of sodium ion channels and the opening of potassium ion channels.

Detailed explanation-5: -Repolarization (K+ efflux) Potassium channels open just as the sodium channels are closing. At this point the net current flow is reversed as potassium ions rush out of the cell, driving the membrane potential back towards the potassium equilibrium potential of –90 mV.