What effect does the sympathetic nervous system have during a stress response?

During a stress response, the sympathetic nervous system plays a critical role in preparing the body for "fight or flight" situations. This activation leads to several physiological changes aimed at enhancing the body’s ability to respond to immediate challenges.

The sympathetic nervous system releases neurotransmitters like norepinephrine, which stimulates the heart to beat faster and with greater force. This results in an increased heart rate and elevated blood pressure, ensuring that more blood is pumped throughout the body. Additionally, this system enhances energy availability by stimulating the breakdown of glycogen in the liver and releasing glucose into the bloodstream, providing the necessary energy substrates for muscle activity.

These responses are essential for improving blood flow to vital organs and active muscle groups, thereby enabling the body to react swiftly and effectively to stressful situations.