The "Undershoot" Phase of After-Hyperpolarization is Due To

Question

The "undershoot" phase of after-hyperpolarization is due to
A) slow opening of voltage-gated sodium channels.
B) sustained opening of voltage-gated potassium channels.
C) rapid opening of voltage-gated calcium channels.
D) slow restorative actions of the sodium-potassium ATPase.
E) ions that move away from their open ion channels.

Accepted Answer

The undershoot phase of after-hyperpolarization occurs due to sustained opening of voltage-gated potassium channels. These channels are responsible for the efflux of potassium ions out of the cell, causing the membrane potential to become more negative than the resting potential. This phase lasts for a short duration until the channels eventually close, leading to the restoration of resting membrane potential by the sodium-potassium ATPase pump.