Question

Action potential of a nerve cell is generated by

• A. $N{a}^{+}$
• B. $K^{+}$
• C. $C{a}^{++}$
• D. $C{l}^{-}$

Answer 1

The correct option is A $N{a}^{+}$

Action potentials are generated by special types of voltage-gated ion channels embedded in a cell's plasma membrane. These channels are shut when the membrane potential is near the resting potential of the cell, but they rapidly begin to open if the membrane potential increases to a precisely defined threshold value. When the channels open (in response to depolarization in transmembrane voltage), they allow an inward flow of sodium ions, which changes the electrochemical gradient, which in turn produces a further rise in the membrane potential. At the beginning of the action potential, the $N{a}^{+}$ channels open and $N{a}^{+}$ moves into the axon, causing depolarization.