Action Potential in an unmyelinated axon

An action potential,depicted as a red band, is propagated in one directional along the axon.During an action potential , the inside of the cell membrane becomes positive with respect to the outside.An action potential generates local current that tends to depolarize the membrane immediately adjacent to the action potential,When depolarization caused by the local currents threshold, a new action potential adjacent to the original one.Action potential propagation occurs in one directional because the recently depolarized area of the membrane is in absolute refractory period and cannot generate an action potential.