Importance of the refractory period

• • Ensures that impulses are propagated (passed) in only one direction: they can’t go backwards.
  • Ensures impulses are discrete: resting potential must be restored before the next action potential can be generated; action potentials cannot merge with each other. 
  • Ensures an upper limit on the frequency of impulse transmission: action potentials cannot merge, so there comes a point at which the maximum action potential frequency must be reached.
• The refractory period keeps impulses discrete and therefore puts an upper limit on action potential frequency.

  This in turn puts an upper limit on the strength of stimulus that can be perceived.