What is the correct term for the return of an action potential's voltage to resting potential?

The term that describes the return of an action potential's voltage to resting potential is repolarization. During an action potential, the membrane potential first rises (depolarization) as sodium channels open and sodium ions flood into the cell. After this rapid rise, potassium channels open, allowing potassium ions to exit the cell, which causes the membrane potential to decrease and move back toward the resting levels. This process of returning to the resting potential is specifically termed repolarization.

The term hyperpolarization refers to a state where the membrane potential becomes more negative than the resting potential, which occurs after repolarization in some cases. Depolarization is the initial phase of the action potential where the membrane potential becomes more positive. Resting potential refers to the baseline state of the membrane potential before an action potential occurs. Understanding these phases and their definitions is crucial for grasping how action potentials function in neuronal signaling and cardiac action potentials.