Question

Correctly identify each of these definitions or examples as either depolarization or hyperpolarization of the plasma membrane.

Answer 1

Depolarisation

A membrane depolarization is a decrease in the potential difference between the outside of a cell and the intracellular medium, on either side of the plasma membrane, most often due to a positive ion input (Na +, Ca ++, etc.) inside the cell or sometimes due to the release of chloride ions, and involved in the mechanisms of transmission of nerve impulses and muscle contraction.

Hyperpolarization:

The depolarization is followed by a repolarization, thanks to the output of an equivalent quantity of ions k + which causes the return to the state of equilibrium. Then there is a hyperpolarization due to the output of more k + ions than Na + ions, because the potassium channels are slow to close. Finally there is a return to the resting potential.

Hyperpolarization is a term opposite to that of depolarization, it refers to values lower than that observed during the resting potential.