Question

An action potential is generated by the movement of: (2 points)

Answer 1

Answer: ions

Explanation:

Answer 2

The action potential is produced by the movement of gated ion channels.

Explanation:

When an action potential or the nerve impulse moves down the 'axon', a change in polarity is observed in the axon's membrane. On receiving a signal from other neuron, the 'sodium' and 'potassium' gated ion channels start opening and closing as the membrane reaches the critical level to which a 'membrane potential' must be 'depolarized' to start an action potential.  

Firstly, the sodium channels open up on the initiation of action potential, because of which sodium moves into the axon which results in depolarization. Secondly, re-polarization takes place as the 'potassium' channels open and 'potassium' moves away from the 'axon'. This brings about a change in polarity in the external and internal medium of the cell. Then, the nerve impulse moves down the axon in only one direction towards the axon terminal from where it sends signals to other neurons.