Which hormone is secreted by the adrenal medulla?

• A. Aldosterone
• B. Cortisol
• C. Noradrenaline
• D. Epinephrine

Answer: (D)

Epinephrine is the hormone released by the adrenal medulla. The medulla acts like a neural tissue of the sympathetic system, secreting catecholamines into the bloodstream when activated. The dominant hormone produced is epinephrine (adrenaline), which rapidly mobilizes energy by boosting heart rate, dilating airways, and increasing blood glucose to prepare for quick action. A smaller amount of norepinephrine is also released from the medulla, but epinephrine is the primary circulating mediator. Aldosterone and cortisol come from the adrenal cortex, not the medulla, with aldosterone regulating electrolyte balance and cortisol supporting metabolism and stress responses.