Epinephrine is primarily associated with which physiological response?

• A. Hunger
• B. Sleep promotion
• C. Fight or flight response
• D. Memory formation

Answer: (C)

Epinephrine is the hormone that mobilizes the body for quick action in stressful situations—the fight-or-flight response. When the sympathetic nervous system kicks in, the adrenal medulla releases epinephrine into the bloodstream, which then acts on various organs to prepare for rapid action. It increases heart rate and the force of heart contractions, raises blood pressure, dilates airways, and boosts blood glucose by promoting glycogen breakdown. Blood flow is redirected to muscles, and alertness is heightened. These rapid, systemic changes are the hallmark of fight-or-flight.

Hunger, sleep promotion, and memory formation are governed by other systems. Hunger is driven by hypothalamic signals and hormones like ghrelin; sleep is regulated mainly by melatonin and circadian processes; memory formation relies on hippocampal and amygdalar circuits with different neurotransmitters. While epinephrine can influence arousal in some contexts, its primary association is with preparing the body for quick, protective action in response to danger or stress.