[Campbell Biology P.1124] According to the text, the refractory period prevents the initiatio... | Practice Question

According to the text, the refractory period prevents the initiation of a second action potential. What is the primary reason for this period?

  • A: An immediate change in the ion concentration gradients across the plasma membrane.
  • B: The voltage-gated potassium channels remain open indefinitely, hyperpolarizing the membrane.
  • C: The voltage-gated sodium channels are inactivated, preventing Na+ inflow.
  • D: The membrane potential is stuck at -55 mV, preventing further depolarization.

Explanation

The text states: 'The "downtime" when a second action potential cannot be initiated is called the refractory period. Note that the refractory period is due to the inactivation of sodium channels, not to a change in the ion concentration gradients across the plasma membrane.'