Final answer:
The refractory period is responsible for preventing another action potential from being initiated. It consists of the absolute refractory period and the relative refractory period. During repolarization, voltage-gated sodium channels close and potassium channels open, allowing potassium ions to exit the cell and restore the resting state.
Step-by-step explanation:
The refractory period, which occurs after depolarization, is responsible for preventing another action potential from being initiated. There are two phases of the refractory period: the absolute refractory period and the relative refractory period. During the absolute refractory period, another action potential cannot start because of the inactivation gate of the voltage-gated Na+ channel.
Once the channel is back to its resting conformation, a new action potential could be started, but only by a stronger stimulus than the one that initiated the current action potential. This is due to the flow of K+ out of the cell. Any Na+ that tries to enter will not depolarize the cell, but will only keep the cell from hyperpolarizing.
The repolarization phase during the refractory period involves the closure of the voltage-gated sodium channels and the opening of potassium channels. This allows potassium ions (K+) to exit the cell, restoring the resting state with a negatively charged interior. This repolarization phase prepares the cell for the initiation of another action potential.