Zoology - Neural Control and Coordination Question with Solution | TestHub

The electrical potential difference across the plasma membrane is called the action potential or as a nerve impulse. At the resting stage, the outer membrane is positively charged and the inner membrane is negatively charged. Upon stimulus, the membrane 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. Later repolarization happens to get back the inner membrane to negatively charged.