Explain the role of ${{Na}^{+}}$ in the generation of action potential

When a stimulus is applied to a nerve, the membrane of the nerve becomes freely permeable to${{Na}^{+}}$. This leads to a rapid influx of ${{Na}^{+}}$ followed by the reversal of the polarity at that site, i.e., the outer surface of the membrane becomes negatively charged and the inner side becomes positively charged. The electrical potential difference across the plasma membrane at the membrane is called the action potential, which is in fact termed as a nerve impulse. Thus, this shows that Na+ ions play an important role in the conduction of nerve impulse.