Which adrenal cortex zone primarily secretes cortisol?

• A. Zona glomerulosa
• B. Zona fasciculata
• C. Zona reticularis
• D. Adrenal medulla

Answer: (B)

The adrenal cortex has three zones that make different hormones, and cortisol comes mainly from the middle layer. This zona fasciculata is the primary site of glucocorticoid production, with secretion driven mainly by ACTH from the pituitary. The outer zona glomerulosa makes mineralocorticoids like aldosterone (regulated largely by the renin–angiotensin system), while the inner zona reticularis produces adrenal androgens such as DHEA. The adrenal medulla is separate from the cortex and releases catecholamines like epinephrine and norepinephrine. So, cortisol is predominantly produced in the zona fasciculata under ACTH control.