As he slowly gets up to investigate, his heart begins to race, his mouth is dry, and he begins to sweat; his "sympathetic nervous system" has been activated.
The sympathetic nervous system (SNS) is a piece of the autonomic nervous system (ANS), which likewise incorporates the parasympathetic nervous system (PNS).
The sympathetic nervous system ordinarily capacities to create restricted alterations, (for example, perspiring as a reaction to an expansion in temperature) and reflex modifications of the cardiovascular framework. Under states of pressure, be that as it may, the whole thoughtful sensory system is enacted, delivering a prompt, boundless reaction called the fight or-flight reaction.