Resting and Acting Potential

Resting and Action Potential

1. Resting potential is when protein pumps pump out Na+ and pump in K+. During this process the inside of the axon is negative while the outside is positive,

2. An action potential starts when a neuron is stimulated by another neuron or the environment. On the axon Na+ ion gates open to allow Na+ to flood the axon and temporally change the inside of the cell positive, Its is also called depolarization.

3. When the impulse passes the Na+ ion gates close and K+ channels open this allows the K+ ions to flow out and changing the axon back to its original state this process is also called repolarization.

The brain and spinal cord

The main part of the central nervous system is the brain, there are 3 parts of the brain that are the major places to relay and process information these places are the cerebrum, cerebellum, and the brain stem. The spinal cord is the main communication link between the brain and the rest of the body, there are 31 pairs of spinal nerves branching out, and many reflexes are passed directly to the spinal cord.

The continue diffusion of sodium ions into the axon depolarizes the membrane more and brings it closer to the threshold. When the potential across the membrane reach the threshold (about -55 mV), additional voltage-gated sodium channel open. When this happens, there is rapid and intense influx of sodium ions into the axon causing the inside of the axon swiftly continues to build up more positive charges, until the membrane potential reaches a potential of about +40 mV compared with the outside.

At this point, the sodium channels are temporary close and are inactivated, so the sodium ions stop diffusing into the axon. At the same time, the voltage-gated potassium channels open. Potassium ions therefore diffuse out of the axon, down their concentration gradient. The outward movement of potassium ions removes positive charge from inside the axon to the outside, thus beginning to return the potential difference to normal.

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