The action potential in an autorhythmic single-unit smooth muscle fiber consists of a depolarizing phase due to the opening of voltage-gated sodium channels, and a repolarizing phase due to opening of voltage-gated potassium channels and closing of voltage-gated sodium channels.

Question

Quizplus · Accepted Answer

In autorhythmic single-unit smooth muscle fibers, the action potential's depolarizing phase is primarily due to the opening of voltage-gated calcium channels, not sodium channels. The repolarizing phase is indeed due to the opening of potassium channels and the closing of the calcium channels.

The Action Potential in an Autorhythmic Single-Unit Smooth Muscle Fiber