Refractory period
The refractory period is a short period of time after the generation of an action potential during which a neuron or muscle fiber cannot fire in response to the next nerve impulse.
During the refractory period, the cell membrane restores its ionic gradients and voltages that were disrupted during the action potential. Because of this, the cell becomes inexcitable for the next impulse.
The refractory period is divided into absolute and relative. During the absolute refractory period, the cell is completely inexcitable. During the relative refractory period, the cell can be excited, but this will require a stronger stimulus.
The refractory period plays an important role in regulating the frequency of action potentials and preventing tetany - excessively frequent impulses that can damage the cell. It allows nerve and muscle tissue to recover between successive impulses.