Question

After a action potential is generated what causes the restoration of membrane potential from hyperpolarising phase to resting phase?

Thank you.

Answer 1

It is sodium potassium pump, which restores the membrane potential. It pumps the sodium ions, which have entered the cell during depolarization, to the outside of the cell. It also pumps the potassium ions, which left the cell duting repolarization and hyperpolarization, to the inside of the cell. 3 sodium ions are pumped out per each two potassium ions, which are transported into the cell. At the same time, energy of ATP is used.