Question

The propagation of electric impulses is caused by ion flow across the axon membrane by the alternating opening and closing of __________ __________ (Na+ and K+).

Answer 1

The propagation of electric impulses is caused by ion flow across the axon membrane by the opening and closing of Na+ and K+ channels.

Step-by-step explanation:

The propagation of electric impulses is caused by ion flow across the axon membrane by the alternating opening and closing of Na+ and K+ channels.

During an action potential, voltage-gated Na+ channels open first, allowing Na+ ions to flow into the cell and depolarize the membrane. This depolarization leads to the opening of voltage-gated K+ channels, allowing K+ ions to flow out of the cell and repolarize the membrane.

Thus, the alternating opening and closing of Na+ and K+ channels is responsible for the propagation of electric impulses along the axon.