1. Nerve fiber membrane maintains resting potential by diffusion of Sodium and Potassium down their concentration gradients as the cell pumps them up the gradients.
2. Neurons receive stimulating, causing local potentials, which may sum to reach threshold.
3. Sodium channels in a local region of the membrane open.
4. Sodium ions diffuse inward, deplorizing the membrane.
5. Potassium channels in the membrane open.
6. Potassium ions diffuse outward, repolarizing the membrane.
7. The resulting action potential causes an electric current that stimulates adjacent portions of the membrane.
8. Series of action potentials occurs sequentially along the length of the nerve fiber as a nerve impulse.
Sodium has high concentration outside cell.