Question

When voltage-gated Na+ channels of a resting neuron open,

A) Na+ enters the neuron.
B) Na+ leaves the neuron.
C) the neuron depolarizes.
D) Na+ enters the neuron and the neuron depolarizes.
E) Na+ leaves the neuron and the neuron depolarizes.

Answer 1

Upon opening of voltage-gated Na+ channels, Na+ enters the neuron causing it to depolarize. Once the neuron depolarizes, K+ channels open leading to repolarization back towards the resting potential.

Step-by-step explanation:

When voltage-gated Na+ channels of a resting neuron open, Na+ enters the neuron and the neuron depolarizes. During an action potential, the opening of these channels is triggered by the neuron reaching its threshold potential. The influx of Na+ ions results in a change from the resting membrane potential towards a more positive value, moving from approximately -70mV to about +30mV, which is the depolarization process. After depolarization, the voltage-gated K+ channels will open, allowing K+ to leave the cell and repolarizing the neuron back towards its resting potential.