Advanced Zona Fasciculata Quiz

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

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

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

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

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

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

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

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

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

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

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

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

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 fasciculata itself
• Zona reticularis

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

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

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

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

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

• It is an avascular connective tissue layer beneath the capsule
• It is a neural crest-derived zone of chromaffin cells producing epinephrine
• 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