Which part of the autonomic nervous system prepares the body for 'fight or flight' by increasing heart rate and redirecting blood flow to muscles?

Which part of the autonomic nervous system prepares the body for 'fight or flight' by increasing heart rate and redirecting blood flow to muscles?

• A. Parasympathetic response
• B. Sympathetic response
• C. Central nervous system
• D. Peripheral nervous system

Answer: (B)

Pushing the body into action in a stressful moment is the job of the sympathetic division of the autonomic nervous system. When this system kicks in, heart rate rises so more blood can be pumped per minute, and the force of each heartbeat increases to boost cardiac output. At the same time, blood vessels shift blood toward active muscles and away from less needed areas, ensuring that oxygen and nutrients reach the muscles quickly. This coordinated set of changes—faster heartbeat and redirected blood flow—creates the rapid energy burst you need for fight or flight, often aided by hormones like adrenaline that amplify the response. In contrast, the parasympathetic system promotes rest and digestion, slowing the heart and conserving energy rather than gearing the body up for quick action. The central nervous system and peripheral nervous system describe broader levels of nervous system organization rather than the specific autonomic adjustments that drive this immediate, mobilizing response.

Pushing the body into action in a stressful moment is the job of the sympathetic division of the autonomic nervous system. When this system kicks in, heart rate rises so more blood can be pumped per minute, and the force of each heartbeat increases to boost cardiac output. At the same time, blood vessels shift blood toward active muscles and away from less needed areas, ensuring that oxygen and nutrients reach the muscles quickly. This coordinated set of changes—faster heartbeat and redirected blood flow—creates the rapid energy burst you need for fight or flight, often aided by hormones like adrenaline that amplify the response.

In contrast, the parasympathetic system promotes rest and digestion, slowing the heart and conserving energy rather than gearing the body up for quick action. The central nervous system and peripheral nervous system describe broader levels of nervous system organization rather than the specific autonomic adjustments that drive this immediate, mobilizing response.