During a relative refractory period:
A) the action potential cannot be initiated.
B) a resting potential exists.
C) the cell membrane is impermeable to Na+ and K+.
D) the action potential can be initiated with a strong stimulus.

Question

Quizplus · Accepted Answer

During the relative refractory period, the cell membrane is still hyperpolarized, but if a strong enough stimulus is applied, it can reach threshold and initiate an action potential. So, option D is the correct choice. Option A is incorrect because the action potential can be initiated with a strong stimulus. Option B is incorrect because the relative refractory period is not a resting period, and the membrane potential is not at resting levels. Option C is incorrect because during the relative refractory period, the cell membrane is still somewhat permeable to both Na+ and K+.

During a Relative Refractory Period