Action Potential

An action potential is an electrical charge that travels along the membrane of a neuron. This occurs through depolarising and repolarising of the membrane.

The differences in concentration of potassium and sodium ions across the membrane creates an electrical charge of -70mV. This is called resting potential.

During depolarisation of the membrane, sodium ion channels open, allowing sodium ions to enter the cell, increasing the positive charge inside the cell. This starts the action potential. Potassium ion channels then open, and potassium ions flow out of the cell, causing the inside of the membrane to become negatively charged and thus repolarising the membrane. This ends the action potential.

Action potential works on an all-or-nothing basis. A threshold of -55mV has to be reached for an action potential to begin. An action potential transmits electrical impulses through the neuron’s axon and to the synapses. Consequently, this allows the brain to communicate and control the rest of the body.

Sources: https://bio.libretexts.org/Bookshelves/Human_Biology/Book%3A_Human_Biology_(Wakim_and_Grewal)/11%3A_Nervous_System/11.4%3A_Nerve_Impulses#:~:text=An%20action%20potential%2C%20also%20called,signals%20from%20a%20nearby%20cell.

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