refractory period
Quick Summary
The refractory period in physiology is a brief interval after a muscle or nerve responds, during which it cannot immediately respond again. This period is crucial for the proper functioning of the nervous system.1
Following an action potential, which is a brief electrical signal in a neuron, the cell membrane undergoes repolarization. This process involves the inactivation of sodium channels and the opening of potassium channels, allowing potassium ions to flow out of the cell. This returns the cell membrane to its polarized state, with the inside negative relative to the outside.2
There are two phases to the refractory period:
* Absolute refractory period: During this time, no matter how strong the stimulus, a second action potential cannot be generated.2
* Relative refractory period: In this phase, another action potential can be generated, but it requires a stronger stimulus than usual.2
This mechanism ensures that nerve impulses are transmitted in one direction and prevents continuous firing.2
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