What effect does the sympathetic nervous system have on blood vessels during stress?

What effect does the sympathetic nervous system have on blood vessels during stress?

• A. It dilates all blood vessels
• B. It constricts certain blood vessels
• C. It keeps blood vessels at a constant size
• D. It causes all blood vessels to relax

Answer: (B)

The sympathetic nervous system, which is activated during stress or a "fight or flight" response, primarily induces vasoconstriction in certain blood vessels. This is a critical physiological response that directs blood flow away from non-essential areas towards vital organs and muscles that need it most during stressful situations. For example, blood vessels supplying the digestive system may constrict, while those supplying the heart and skeletal muscles may be preserved or even moderately dilated due to other factors in the sympathetic response, like the release of epinephrine. This strategic constriction enhances perfusion pressure and ensures that oxygen-rich blood is rapidly delivered to areas that will need to respond to a perceived threat, enhancing overall physical preparedness. Therefore, the role of vasoconstriction in certain blood vessels during stress is crucial for maintaining optimal blood flow and ensuring the body can respond effectively to challenges.

The sympathetic nervous system, which is activated during stress or a "fight or flight" response, primarily induces vasoconstriction in certain blood vessels. This is a critical physiological response that directs blood flow away from non-essential areas towards vital organs and muscles that need it most during stressful situations. For example, blood vessels supplying the digestive system may constrict, while those supplying the heart and skeletal muscles may be preserved or even moderately dilated due to other factors in the sympathetic response, like the release of epinephrine.

This strategic constriction enhances perfusion pressure and ensures that oxygen-rich blood is rapidly delivered to areas that will need to respond to a perceived threat, enhancing overall physical preparedness. Therefore, the role of vasoconstriction in certain blood vessels during stress is crucial for maintaining optimal blood flow and ensuring the body can respond effectively to challenges.