The Refractory Period (AQA A Level Biology): Revision Note

The refractory period

• During repolarisation the voltage-gated potassium ion channels remain open for longer than needed to restore resting potential, and the axon membrane becomes hyperpolarised

• The time during which the membrane is hyperpolarised is known as the refractory period

• The refractory period is very important as it ensures that:

  • new action potentials are generated ahead, rather than behind, the original action potential, so nerve impulses are only ever transmitted in one direction

  • nerve impulses are separate events, rather than merging together