Why do Na⁺ ions enter the cell when voltage-gated Na⁺ channels are opened in neurons?
A) because the Na⁺ concentration is much lower outside the cell than it is inside
B) because the Na⁺ ions are actively transported by the sodium-potassium pump into the cell
C) because 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) because 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

Voltage-gated Na⁺ channels open in response to a depolarization of the cell membrane, which means the inside of the cell becomes less negative. Because the Na⁺ concentration is much higher outside the cell than it is inside, the Na⁺ ions are attracted to the negatively charged interior and move into the cell through the open channels. The sodium-potassium pump is not involved in this process as it actively transports Na⁺ ions out of the cell and K⁺ ions into the cell.

Why Do Na⁺ Ions Enter the Cell When Voltage-Gated Na⁺