What term describes the period after an action potential during which the neuron is less excitable?

• A. Resting Potential
• B. Action Potential
• C. Refractory Period
• D. Hyperpolarization

Answer: (C)

The refractory period describes the period after an action potential during which the neuron is less excitable. After the spike, voltage-gated Na+ channels become inactivated and must recover before they can open again, and many K+ channels remain open, pushing the membrane toward or beyond the resting potential. This creates two phases: an absolute refractory period when no stimulus can trigger another action potential because Na+ channels are inactivated, and a relative refractory period when a stronger-than-normal stimulus is needed because some Na+ channels have recovered but the membrane is still hyperpolarized from K+ efflux. This period helps ensure unidirectional conduction and caps how frequently a neuron can fire. Resting potential is the baseline state, and hyperpolarization is the afterpotential during the relative refractory phase, not the term for the overall post-spike period.