Question

Explain the process of depolarisation of the membrane of a nerve fibre.

Answer 1

The nerve fibre is at resting phase when it is not stimulated by any impulse. They possess a potential difference along the membrane which is known as resting potential (-70mv). The membrane is negatively charged inside due to the lower concentration of potassium ions and positively charged outside due to the high concentration of sodium ions.

When an electrical stimulus is received by a nerve fibre, an action potential is generated. The membrane becomes permeable to sodium ions than to potassium ions. This results in a positive charge inside and negative charge outside the nerve fibre. Hence, the membrane is said to be depolarised.