Which answer explains why Na+ ions enter the cell when voltage-gated Na+ channels are opened in neurons?
A) the Na+ concentration is much lower outside the cell than it is inside the cell
B) the Na+ ions are actively transported by the sodium-potassium pump into the cell
C) the Na+ concentration is much higher outside the cell than it is inside, and the Na+ ions are attracted to the negatively charged interior
D) the Na+ concentration is much higher outside the cell than it is inside, and the Na+ ions are actively transported by the sodium-potassium pump into the cell

Question

Quizplus · Accepted Answer

The Na+ concentration is indeed much higher outside the neuron than inside, and because the interior of the neuron is negatively charged relative to the outside, Na+ ions are attracted into the cell when voltage-gated Na+ channels open. This creates a concentration and electrical gradient that drives the passive diffusion of Na+ ions into the cell.

Which Answer Explains Why Na+ Ions Enter the Cell When