When is an action potential initiated? When A. the resting membrane potential changes from −70 mV to +30 mV. B. a nerve impulse has caused some muscle action to be produced. C. the potassium ‘gates’ in the cell membrane open and potassium ions fl ood into the cell. D. a stimulus, which is above the threshold level, is applied to a receptor.
Option D. Action potential initiated when a stimulus, which is above the threshold level, is applied to a receptor.
