As Harry's heart and pulse are racing, thus, his physiological responses can be best accredited to his sympathetic nervous system.
The sympathetic nervous system refers to the segment of the autonomic nervous system that also involves the parasympathetic nervous system. The sympathetic nervous system stimulates what is generally known as the fight or flight response.
In reply to a stressor, the sympathetic nervous system enhances the flow of blood to the muscle and tension, dilates pupil, increases perspiration and arterial blood pressure, and accelerates heart rate and respiration.
