Final answer:
Potassium leak channels and the Na+/K+ pump restore the resting membrane potential after an action potential through the processes of repolarization and subsequent hyperpolarization.
Step-by-step explanation:
After the depolarization phase of an action potential, the membrane returns to its resting state through a process called repolarization. During repolarization, voltage-gated sodium channels close, while potassium leak channels continue to allow potassium ions to move out of the cell. Additionally, the Na+/K+ pump actively transports ions to restore the resting membrane potential.
This process brings the membrane potential back to its resting value of -70 mV, indicating repolarization. However, the membrane potential actually overshoots this value, resulting in a period of hyperpolarization. During hyperpolarization, the membrane voltage is below -70 mV, as potassium ions have reached equilibrium. This occurs because potassium channels are slightly delayed in closing, leading to a short period of hyperpolarization.
The process of restoring the resting membrane potential after an action potential involves a few key steps. Initially, the depolarization of the membrane occurs when sodium ions (Na+) rush into the cell, which increases the cellular charge. When the action potential peaks, sodium channels close and potassium channels open, leading to the efflux of K+ ions and the subsequent repolarization of the cell. However, repolarization not only returns the membrane potential to its resting level (around -70 mV) but also results in a period of hyperpolarization, where the membrane potential temporarily becomes even more negative than the resting level due to potassium channels being slightly delayed in closing. Finally, the Na+/K+ pump, which actively transports sodium out of the cell and potassium into it, helps restore and maintain the resting membrane potential.