Question

The absolute refractory period during nerve impulse conduction is the period of
A. Repolarisation
B. Depolarisation
C. Both repolarisation and depolarisation
D. Neither repolarisation nor depolarisation

Answer 1

Hint:
The functional and structural units of the nervous system are known as neurons. Generally, neurons are known as nerve cells. It is the longest cell in the human body and transmits information in the form of electrical impulses.

Complete step by step solution:
Nerve cell length can vary from 1mm to 1m. Cyton is the main part of the neuron and is also known as the cell body or soma. It is covered by a protective membrane.
The refractory period in a neuron is the time in which nerve cells are unable to fire up a nerve impulse or action potential. There are two types of subsets is existed in neurons the absolute refractory period and another is the relative refractory period.
The absolute refractory period is caused in neurons due to the inactivation of Na⁺ channels as they originally opened to depolarize the membrane. The interior membrane becomes positively charged once depolarization occurs. At this time the membrane potential reaches approximately +52mV and voltage-gated Na⁺ Channels remain to deactivate for a brief period of time. This is known as the absolute refractory period at this period the second phase cannot be created. It corresponds with the peak of depolarization in the membrane of the axon. Subsequently, the relative refractory period coincides with the repolarization period. So, in this period the nerve is not able to transmit the impulse.

Option ‘D’ is correct

Note:
Nerve cells are a communication network that carries messages to and from the brain and spinal cord to all the parts of the body with the help of a complex network of nerves.