Adrenal Cortex Flashcards

Examine the adrenal cortex, its three histological zones, steroid hormone production, vascular organization, and endocrine regulation.

Card 1 of 30Question

What is the adrenal cortex?

The outer, steroid-producing region of the adrenal gland surrounding the adrenal medulla.

In This Section

1. What is the adrenal cortex?

The outer, steroid-producing region of the adrenal gland surrounding the adrenal medulla.

2. What are the three zones of the adrenal cortex from superficial to deep?

Zona glomerulosa, zona fasciculata, and zona reticularis.

3. What structure immediately surrounds the adrenal cortex?

A dense connective tissue capsule.

4. Which adrenal cortical zone lies directly beneath the capsule?

The zona glomerulosa.

5. How are cells arranged in the zona glomerulosa?

In rounded clusters and curved arches separated by capillaries.

6. Which class of steroid hormones is primarily produced by the zona glomerulosa?

Mineralocorticoids, predominantly aldosterone.

7. What is the primary physiological action of aldosterone?

It promotes renal sodium reabsorption and potassium excretion.

8. Which enzyme enables the zona glomerulosa to synthesize aldosterone?

Aldosterone synthase (CYP11B2).

9. What are the principal regulators of aldosterone secretion?

Angiotensin II and extracellular potassium concentration.

10. Which adrenal cortical zone is the thickest?

The zona fasciculata, comprising most of the cortical thickness.

11. How are cells organized in the zona fasciculata?

In long, straight cords separated by sinusoidal capillaries.

12. Why do zona fasciculata cells often appear pale and vacuolated in routine histological sections?

Their abundant lipid droplets are dissolved during routine tissue processing.

13. Which class of hormones is primarily produced by the zona fasciculata?

Glucocorticoids, predominantly cortisol.

14. Which pituitary hormone primarily stimulates cortisol secretion?

Adrenocorticotropic hormone (ACTH).

15. Which adrenal cortical zone lies immediately adjacent to the medulla?

The zona reticularis.

16. How are cells arranged in the zona reticularis?

In irregular, branching, interconnected cords.

17. Which pigment may accumulate in zona reticularis cells with age?

Lipofuscin pigment.

18. Which hormones are primarily secreted by the zona reticularis?

Adrenal androgens, mainly dehydroepiandrosterone (DHEA) and its sulfate (DHEAS).

19. What is the principal precursor used for steroid hormone synthesis in the adrenal cortex?

Cholesterol.

20. Which organelles are especially prominent in steroid-producing adrenal cortical cells?

Smooth endoplasmic reticulum and mitochondria with tubular cristae.

21. Which enzyme initiates steroidogenesis by converting cholesterol into pregnenolone?

Cholesterol side-chain cleavage enzyme (CYP11A1), located in mitochondria.

22. Why does the zona glomerulosa not normally produce significant amounts of cortisol?

It lacks 17-alpha-hydroxylase activity (CYP17A1), which is required for cortisol synthesis.

23. What is the main pattern of blood flow through the adrenal cortex?

Blood flows through cortical sinusoidal capillaries toward the adrenal medulla.

24. Which cortical hormone reaches the adrenal medulla through cortical blood flow and promotes epinephrine synthesis?

Cortisol.

25. What is the embryological origin of the adrenal cortex?

Mesoderm derived from the coelomic epithelium of the posterior abdominal wall.

26. What are the two main cortical components of the developing fetal adrenal gland?

A large fetal zone surrounded by a thinner definitive zone.

27. What happens to the fetal zone of the adrenal cortex after birth?

It undergoes rapid involution, contributing to a marked reduction in adrenal gland size.

28. Which endocrine disorder results from chronic excessive cortisol secretion?

Cushing syndrome.

29. What is the most common enzymatic defect causing congenital adrenal hyperplasia?

21-hydroxylase deficiency, which impairs cortisol synthesis and often aldosterone synthesis.

30. Which adrenal cortical disorder is characterized by autonomous excessive aldosterone production?

Primary aldosteronism, also called Conn syndrome when caused by an aldosterone-producing adenoma.