JMSS Science Practice Test

The body's stress response is coordinated mainly by cortisol, a glucocorticoid released from the adrenal cortex as part of the HPA axis. When stress signals reach the hypothalamus, it triggers the pituitary to release ACTH, which prompts the adrenal cortex to secrete cortisol. Cortisol mobilizes energy by increasing glucose production and availability, reshapes metabolism to meet prolonged demands, and helps regulate immune and inflammatory responses—supporting the body during ongoing stress. This long-term energy management and systemic adjustment make cortisol the hormone most closely linked to stress. Adrenaline, by contrast, acts quickly to prepare for immediate “fight or flight” actions, raising heart rate and blood pressure for rapid responses, while estrogen and testosterone are mainly involved in reproductive and sexual functions.