The membrane potential at the peak of the

action potential approaches closer to the equilibrium potential of Na⁺, as Na⁺

permeability is highest at that point.

The sodium-potassium pump (Na⁺/K⁺ ATPase)

is responsible for returning the membrane to resting potential post hyperpolarization.

The repolarization phase is primarily due

to the opening of voltage-gated Na⁺ channels and the influx of Na⁺ ions into

the cell.

Hyperpolarization is only dependent on

the inactivation loop of sodium channels, which allows excess K⁺ to exit the

cell beyond the resting potential level.

During the absolute refractory period,

another action potential can be generated, but only with a larger-than-normal

stimulus.