Which statement correctly describes what causes the second voltage-gated na⁺ channel to open?
a. as na⁺ ions enter the cell through the first channel, they spread out from the channel. when these na⁺ ions reach the second channel, it opens.
b. as na⁺ ions enter the cell through the first channel, na⁺ ions outside the cell move toward the open na⁺ channel.
c. when the concentration of na⁺ ions near the second channel becomes low enough, the second channel opens.
d. after the first channel opens, the movement of na⁺ ions (both inside and outside the cell) alters the na⁺ ion distribution across the membrane near the second channel, causing it to open.
e. after the first channel opens, the movement of many types of ions (both inside and outside the cell) alters the distribution of charges near the second channel, causing it to open.

what causes the second voltage-gated Na⁺ channel to open is that after the first channel opens, the movement of many types of ions (both inside and outside the cell) alters the distribution of charges near the second channel, causing it to open. Option D

Explanation:

Voltage-gated sodium channels are known as transmembrane proteins that cause rapid depolarization resulting to upstroke of action potentials in neurons and are thus important to nerve impulse conduction.

Our nervous system contains cells, the neurons that send information to and from the brain and spinal cord .

Sensory nerves receive stimuli from receptors by a change in voltage or membrane potential that occurs across the plasma membrane.This voltage difference is determined by the relative concentration of potassium and sodium ions inside compared with outside of the nerve cell. Hope this helps. Thanks