Advanced Zona Fasciculata Quiz

Q1. What is the acute steroidogenic effect of ACTH on cholesterol handling in zona fasciculata cells?

• It converts cholesterol directly into catecholamines
• It promotes cholesterol delivery to mitochondria
• It blocks cholesterol uptake
• It packages cortisol into synaptic vesicles

Q2. Which protein is crucial for transferring cholesterol to the inner mitochondrial membrane during adrenal steroidogenesis?

• Phenylethanolamine N-methyltransferase
• Renin
• Tyrosine hydroxylase
• Steroidogenic acute regulatory protein

Q3. Which enzyme catalyzes the first committed conversion of cholesterol in adrenal steroidogenesis?

• Dopamine beta-hydroxylase
• CYP11A1 cholesterol side-chain cleavage enzyme
• PNMT
• Aldosterone synthase

Q4. Why are glucocorticoids generally released soon after synthesis rather than stored in large secretory granules?

• Steroids diffuse through cell membranes after synthesis
• Cortisol is stored only in the adrenal medulla
• The cells lack a plasma membrane
• Steroids are insoluble in lipids

Q5. Why can chronic ACTH excess enlarge the zona fasciculata?

• ACTH promotes hypertrophy and hyperplasia of the zone
• ACTH blocks all steroidogenic enzymes
• ACTH affects only the adrenal medulla
• ACTH destroys fasciculata cells

Q6. Why can prolonged exogenous glucocorticoid therapy cause zona fasciculata atrophy?

• Glucocorticoids directly convert fasciculata into medulla
• The zona fasciculata depends only on angiotensin II
• Suppression of ACTH removes trophic stimulation
• Therapy increases ACTH continuously

Q7. Which cortical zone is generally less dependent on ACTH trophic support than the zona fasciculata?

• Adrenal medulla as a cortical zone
• Zona glomerulosa
• Zona reticularis
• Zona fasciculata itself

Q8. How does blood leaving the zona fasciculata influence adrenal medullary function?

• It carries urine into the medulla
• It prevents chromaffin cells from receiving oxygen
• It delivers aldosterone that blocks catecholamines
• It delivers cortisol that promotes PNMT expression

Q9. What structural relationship supports rapid transfer of newly synthesized cortisol into the circulation?

• A thick keratinized barrier around every cell
• Cartilage separating cells from vessels
• Direct ducts from the cortex to the renal pelvis
• Close apposition to fenestrated sinusoidal capillaries

Q10. Which statement best integrates zona fasciculata anatomy and function?

• It is the outermost cortical zone controlled primarily by angiotensin II
• It is a thick ACTH-responsive steroidogenic zone whose radial histology and vascular organization support glucocorticoid secretion
• It is an avascular connective tissue layer beneath the capsule
• It is a neural crest-derived zone of chromaffin cells producing epinephrine