Which phases of the action potential represent the absolute refractory period?
I. Phase 0
II. Phase 1
III. Phase 2
IV. First half of Phase 3
V. First half of Phase 4

Question

Quizplus · Accepted Answer

The absolute refractory period includes Phase 0 (depolarization), Phase 1 (initial repolarization), Phase 2 (plateau phase), and the first half of Phase 3 (rapid repolarization). During this time, the cardiac cells cannot be excited again, ensuring that the heart has time to fill with blood before the next contraction.

Which Phases of the Action Potential Represent the Absolute Refractory