Question

Describe how sections of the axolemma are repolarized back to resting potential behind the migrating action potential

Answer 1

Repolarization is the reverse of depolarization in which a neuron attempts to achieve the Resting Membrane Potential or it's resting polarised state. When a particular region of axon of neuron undergo depolarization, it's membrane potential gets less negative than threshold, which results in generation of action potential. Depolarizing current flows to adjacent region of axolemma. However, the previous region must be repolarized to recieve a new impulse if any.

Repolarization is done by:

• Closing of Inactivation gate or 'h' gate of sodium channel. So there will be no influx of sodium ions. Consequently, there will be no further depolarization or less negative membrane potential.

• Opening of potassium channel allows efflux of potassium ions. Since potassium ion will leave the axolemma, membrane potential will become more negative. This helps to achieve the Resting Membrane Potential once again.