Final answer:
The inactivation of voltage-gated Na+ channels during nerve conduction is associated with the depolarization phase of an action potential. After Na+ ions flow into the cell and cause depolarization, these channels close and enter an inactivated state, leading to a refractory period where they cannot be opened. This is coincident with the opening of voltage-gated K+ channels, which facilitate repolarization and transient hyperpolarization of the cell membrane.
Step-by-step explanation:
During nerve conduction, the inactivation of voltage-gated Na+ channels is triggered after the channels open due to depolarization and the membrane potential reverses, reaching around +30 mV. This event is critical as it proceeds the repolarization phase of an action potential, which is the return of the membrane potential toward the resting state.
Following this depolarization, voltage-gated K+ channels open, allowing K+ to exit the cell and aiding in reestablishing the negative resting membrane potential. This outflow of K+ eventually leads to hyperpolarization, temporarily making the cell interior more negative than its normal resting potential. Throughout this, the Na+ channels remain inactivated, creating a refractory period where no new action potential can occur until the membrane potential returns near to its resting state and the Na+ channels reset.