What happens to the membrane at site A when a stimulus is applied?

The outer surface of the axonal membrane possesses a positive charge while its inner surface becomes negatively charged and therefore is polarised The sodium-potassium pump transports 3 Na⁺ ions outwards for 2 K⁺ ions into the cell.The action potential of the plasma membrane of a neuron is the electrical potential difference across the plasma membrane.The rise in permeability to Na⁺ is short-lived and is followed by a rise in permeability to K⁺. K⁺ diffuses outside the membrane, restoring the resting potential of the membrane.