Question

Which of the following is the main intracellular ion involved in nerve impulse transmission ?

• A. $C{a}^{2+}$
• B. $K^{+}$
• C. $N{a}^{+}$
• D. $M{g}^{2+}$

Answer 1

The correct option is B $K^{+}$

Na${}^{+}$ is mainly extracellular ion while K${}^{+}$ is intracellular ion during nerve conduction.

As an action potential (nerve impulse) travels down an axon there is a change in polarity across the membrane of the axon. In response to a signal from another neuron, sodium- (Na+) and potassium- (K+) gated ion channels open and close as the membrane reaches its threshold potential. Na+ channels open at the beginning of the action potential, and Na+ moves into the axon, causing depolarization. Repolarization occurs when the K+ channels open and K+ moves out of the axon, creating a change in polarity between the outside of the cell and the inside.

So, the correct option is 'K${}^{+}$'.