Question

Depolarization of axolemma during nerve conduction takes place because _____.

• A. Equal amount of Na⁺ and K⁺ move across the axolemma
• B. Na⁺ ions move inside
• C. More Na⁺ ions outside
• D. More K⁺ ions outside

Answer 1

The correct option is B

Na⁺ ions move inside

Depolarization of a nerve cell membrane occurs during the passage of an action potential along the axon where the nerve is transmitting an impulse. During depolarization, the Voltage-gated Na⁺ channels open, and Na⁺ rush into the axon. Entry of sodium ions leads to depolarization (reversal of polarity) of the nerve membrane. This membrane depolarization causes the opening of voltage-gated K⁺ channels, allowing K⁺ ions to exit and repolarization of the membrane.