How does ACTH influence adrenal cortex zones?

How does ACTH influence adrenal cortex zones?

• A. ACTH stimulates zona glomerulosa to produce aldosterone
• B. ACTH stimulates the zona fasciculata to produce cortisol; has little effect on zona glomerulosa; aldosterone regulated by RAAS
• C. ACTH stimulates the adrenal medulla to secrete catecholamines
• D. ACTH has no effect on adrenal cortex

Answer: (C)

ACTH acts mainly on the adrenal cortex, particularly the zona fasciculata and zona reticularis, to stimulate production and release of glucocorticoids (cortisol) and adrenal androgens by upregulating steroidogenic enzymes. It has little effect on the zona glomerulosa, where aldosterone is governed primarily by the renin–angiotensin system and potassium levels. The adrenal medulla, on the other hand, secretes catecholamines in response to sympathetic nervous system input, not ACTH. So ACTH drives cortisol production in the cortex, while aldosterone is controlled by RAAS and potassium, and medullary catecholamine release is driven by sympathetic signals.

ACTH acts mainly on the adrenal cortex, particularly the zona fasciculata and zona reticularis, to stimulate production and release of glucocorticoids (cortisol) and adrenal androgens by upregulating steroidogenic enzymes. It has little effect on the zona glomerulosa, where aldosterone is governed primarily by the renin–angiotensin system and potassium levels. The adrenal medulla, on the other hand, secretes catecholamines in response to sympathetic nervous system input, not ACTH. So ACTH drives cortisol production in the cortex, while aldosterone is controlled by RAAS and potassium, and medullary catecholamine release is driven by sympathetic signals.