Biological Bases of Behavior Practice Test

The fight-or-flight response hinges on a rapid hormonal signal that prepares the body for quick action. Adrenaline, also called epinephrine, is released by the adrenal medulla when the sympathetic nervous system is activated. It quickly raises heart rate and blood pressure, opens airways, and mobilizes glucose and fatty acids to fuel muscles, helping you respond fast to a threat. Cortisol from the adrenal cortex supports energy over a longer timescale rather than an immediate burst, testosterone is a sex hormone, and insulin from the pancreas regulates blood glucose—none of these drive the quick, arousal-focused changes of fight-or-flight in the moment.