The resting state is immediately restored at a depolarised site on the axon by the diffusion of 

The resting state is restored at a depolarised site on the axon through the movement of K+ out of the axon. The process is termed repolarisation. During an action potential, the axon membrane depolarises as Na+ enter the cell, causing a change in the electrical charge across the membrane. To restore the resting state, the cell needs to repolarise, bringing the membrane potential back to its resting state. The repolarisation phase involves the movement of potassium ions out of the axon.