The Sympathetic Nervous System is a part of the autonomic nervous system that prepares the body for stressful or emergency situations. It activates the "fight or flight" response, increasing heart rate, dilating airways, and redirecting blood flow to essential muscles. This response helps the body react quickly to perceived threats. When the sympathetic nervous system is activated, it releases hormones like adrenaline and noradrenaline, which enhance alertness and energy levels. This system works in balance with the parasympathetic nervous system, which promotes relaxation and recovery after stress has passed. Together, they help maintain the body's overall stability.