Question

Explain the process of conduction of a nerve impulse along 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.

The potential generated at this phase is known as the action potential. As the action potential reaches its maximum value, the membrane potential gets reversed and this state is known as repolarization. By sequential activity of the nerve conduction, it reaches the terminal end of the axon and stimulates the synaptic vesicles which release the neurotransmitters. The neurotransmitters cross the synaptic membrane and reach the dendrite of the next neuron.