Which of the following reactions occurs during a sympathetic response?

During a sympathetic response, the body prepares for "fight or flight," which involves various physiological changes to enhance survival in stressful situations. One of the key reactions that occur is the increase in glucose levels in the blood. This happens because the sympathetic nervous system stimulates the liver to break down glycogen into glucose (glycogenolysis) and release it into the bloodstream, providing the body with immediate energy to respond to a threat.

The sympathetic response increases energy availability, which is crucial for heightened physical activity and increased metabolic demands. This mechanism supports the idea of preparing the body for intense physical exertion.

The other reactions associated with a sympathetic response differ fundamentally from the increase in glucose levels. For instance, constricted bronchi and increased digestion are not part of the sympathetic response, as the body aims to optimize respiratory efficiency and redirect energy away from non-essential functions like digestion during such stressful situations. Instead, sympathetic activation typically leads to bronchodilation to allow more air into the lungs and an overall decline in digestive activity, ensuring that resources are focused on immediate survival needs.