When an axon is stimulated to threshold,the voltage-gated A)K⁺ channels open before the voltage-gated Na⁺ channels B)Na⁺ channels are activated and then inactivated C)K⁺ channels open at the same time as the voltage-gated Na⁺ channels D)K⁺ channels are opened when Na⁺ binds to the channel E)All of the choices are correct

Question

Quizplus · Accepted Answer

When an axon is stimulated to threshold, the voltage-gated Na+ channels are activated and lead to rapid depolarization of the membrane. These channels then inactivate, causing a brief period of hyperpolarization. The voltage-gated K+ channels then open, allowing K+ to leave the cell and repolarize the membrane. Therefore, choice B is the best answer as it correctly explains the activation and inactivation of the voltage-gated Na+ channels.

When an Axon Is Stimulated to Threshold,the Voltage-Gated