HPA Axis CRH ACTH Cortisol — FRCA Primary MCQ
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Correct answer: D — Hypothalamic CRH stimulates anterior-pituitary ACTH, then zona-fasciculata cortisol
The best answer is “Hypothalamic CRH stimulates anterior-pituitary ACTH, then zona-fasciculata cortisol”. CRH released from the hypothalamus stimulates corticotrophs in the anterior pituitary to release ACTH, which stimulates cortisol synthesis in the adrenal zona fasciculata. Cortisol exerts negative feedback at hypothalamic and pituitary levels. Aldosterone is regulated chiefly by potassium and the renin–angiotensin system, not the HPA axis.
Reference: Royal College of Anaesthetists, Primary FRCA Syllabus 2021: https://www.rcoa.ac.uk/sites/default/files/documents/2026-01/Primary-FRCA-Syllabus.pdf