What is "sympathetic nervous system"?

The sympathetic nervous system is a division of the autonomic nervous system that coordinates the body's response to stress and emergencies. It activates the "fight or flight" response, increasing heart rate, constricting blood vessels, and stimulating the release of adrenaline. The sympathetic nervous system helps prepare the body for action and is involved in various physiological processes, including regulating blood pressure, body temperature, and metabolism.