The "fight or flight" response is primarily mediated by which part of the nervous system?

The "fight or flight" response is primarily mediated by the sympathetic nervous system. This system is responsible for initiating physiological changes that prepare the body to respond to perceived threats or stressors. When activated, the sympathetic nervous system triggers a cascade of responses such as increased heart rate, elevated blood pressure, and enhanced blood flow to muscles, which collectively prepare the body for quick action.

The activation of this system is characterized by the release of adrenaline and norepinephrine, hormones that further enhance the body's energy levels and readiness for immediate physical activity. This reaction contrasts with the parasympathetic nervous system, which promotes a "rest and digest" state that conserves energy and calms the body after stress.

The central nervous system encompasses both the brain and spinal cord, serving as the main control center for processing information but is not solely responsible for the "fight or flight" response itself. The enteric nervous system, while it plays a crucial role in regulating gastrointestinal functions, does not directly mediate the body's reaction to stress. Therefore, the sympathetic nervous system is correctly identified as the primary mediator in the context of the "fight or flight" response.