Question

When a neuron is in a resting state i.e. not conducting any impulse, the axonal membrane is?

• A. Comparatively more permeable to K+ ions and nearly impermeable to Na+ ions
• B. Equally permeable to both Na+ and K+ ions
• C. Impermeable to both Na+ and K+ ions
• D. Comparatively more permeable to Na+ ions and nearly impermeable to K+ ions

Answer 1

The correct option is A

Comparatively more permeable to K+ ions and nearly impermeable to Na+ ions

The correct option is A.

Explanation for correct option:

1. A resting membrane is a condition in which there is no propagation of the impulse. As impulse passes from one part of the neuron to another the conductivity of ions in the previous part decreases & ion channels also start closing.
2. During this stage, K⁺ ion channels are opened as they slow workers.
3. They generally take more time to close and hence they remain open. Na⁺ channels are also closed as impulse passes off.
4. Due to the presence of opened potassium channels, the permeability of potassium is more than the Na⁺ channels which are closed and the membrane is usually impermeable to Na⁺. So resting membrane of the axon has more K⁺ inside and more Na⁺ outside.

Final answer: When a neuron is resting i.e. not conducting any impulse, the axonal membrane is Comparatively more permeable to K+ ions and nearly impermeable to Na+ ions.