What part of the nervous system is primarily affected by stress?

Stress primarily affects the sympathetic nervous system, which is responsible for the body’s "fight or flight" response. When confronted with a stressor, the sympathetic nervous system gets activated, leading to physiological changes such as increased heart rate, elevated blood pressure, and heightened alertness. This response prepares the body to react quickly to perceived threats, which is crucial for survival.

The central nervous system, while involved in processing stress and coordinating responses, is not the primary system that reacts to stress. The parasympathetic nervous system, on the other hand, is responsible for "rest and digest" functions and serves to calm the body after a stress response, counteracting the effects of the sympathetic nervous system. The enteric nervous system manages gastrointestinal functions and is less directly involved in the acute stress response compared to the sympathetic system. Therefore, the sympathetic nervous system is the correct answer because it is the primary system activated during stressful situations leading to immediate bodily responses.