Question

Which of the following chemical changes is responsible for repolarisation of the membrane of axons?

• A. Opening of $Na^{+}VGC$ and rapid influx of $Na^{+}$ ions
• B. Opening of $K^{+}VGC$ and rapid influx of $K^{+}$ ions
• C. Opening of $Na^{+}VGC$ and closing of $K^{+}$ VGC
• D. Closing of $Na^{+}VGC$ and opening of $K^{+}VGC$

Answer 1

Answer: (D)

The neurons or nerve cells possess some special features. The cells can be excited. The nerve impulse is a series of wave of bioelectrical or electrochemical disturbances passing along a neuron. The transmission of the nerve impulse along the long nerve fibre/axon tube is a result of electrical charges across the neuronal membrane during conduction of an excitation. There is depolarisation and repolarisation. During repolarisation, there is closing of Na⁺ voltage gated channels and opening of K⁺ voltage gated channels.