Question

In the given diagram which stage of conduction of nerve impulse through nerve fibre is observed:-

• A. Polarisation
• B. Depolarisation
• C. Repolarisation
• D. Hyperpolarisation

Answer 1

The correct option is A Polarisation

The nerve impulse is the transfer of signals through nerve fibers. It requires the sodium-potassium pump to create a potential gradient.

• Polarisation is the resting potential, here axon has more Na${}^{+}$ than K${}^{+}$ and outside axon more K${}^{+}$ nad less Na${}^{+}$. This creates a concentration gradient which results in the movement of 3 Na${}^{+}$ outside and 2K${}^{+}$ inside.
  
• Depolarisation is the process where due to pressure Na${}^{+}$ channels permit more influx of Na${}^{+}$ and K${}^{+}$ channel closes themselves, this causes depolarization of the membrane.
• Repolarization is the process in which due to the depolarization of the membrane concentration of Na${}^{+}$ increases thus closing its channel and opening the channel of K${}^{+}$ due to its low concentration.

So, the correct is 'Polarisation'.