Q: Which equation describes the conversion of cortisol to cortisone by 11\beta-hydroxysteroid dehydrogenase?

$$\text{Cortisol} + NAD^+ \xrightarrow{11\beta HSD2} \text{Cortisone} + NADH$$

Question 1

Which region of the adrenal gland is responsible for the synthesis of mineralocorticoids, and what is the primary mineralocorticoid produced?

Accepted Answer

Zona glomerulosa; aldosterone

Question 2

A patient presents with hypernatremia, hypokalemia, and metabolic alkalosis. Which adrenal disorder is most likely responsible for these symptoms?

Accepted Answer

Conn's syndrome

Question 3

Which enzyme catalyzes the conversion of cholesterol to pregnenolone in the mitochondria of adrenal cortical cells?

Accepted Answer

CYP11A1 (side-chain cleavage enzyme/desmolase)

Question 4

What is the effect of glucocorticoids on carbohydrate metabolism in the liver?

Accepted Answer

Increase gluconeogenesis and decrease glucose uptake

Question 5

Which hormone is released episodically in response to stress and follows a circadian rhythm, leading to a 24-hour pattern of glucocorticoid secretion?

Accepted Answer

ACTH (Adrenocorticotropic hormone)

Question 6

Aldosterone increases sodium reabsorption in the distal tubule of the kidney. Which equation best represents the osmotic effect of sodium reabsorption on water movement?

Accepted Answer

$$\Delta \Psi = RT \ln \left( \frac{[Na^+]_{interstitial}}{[Na^+]_{lumen}} \right)$$

Question 7

Which zone of the adrenal cortex lacks the enzyme 17\alpha-hydroxylase/17,20-desmolase and therefore cannot produce glucocorticoids or androgens?

Accepted Answer

Zona glomerulosa

Question 8

What is the primary function of 11\beta-hydroxysteroid dehydrogenase in mineralocorticoid-responsive cells?

Accepted Answer

Converts cortisol to inactive cortisone, preventing glucocorticoid activation of mineralocorticoid receptors

Question 9

Which of the following best describes the negative feedback regulation of the hypothalamic-pituitary-adrenal (HPA) axis?

Accepted Answer

High cortisol levels inhibit CRH and ACTH release

Question 10

A patient with Addison’s disease is likely to exhibit which of the following symptoms due to deficiencies in both mineralocorticoids and glucocorticoids?

Accepted Answer

Hypotension and hypoglycemia

Question 11

Which steroid hormone is the major circulatory androgen secreted by the adrenal gland, and which zone is responsible for its sulfation?

Accepted Answer

DHEA-S; zona reticularis

Question 12

Which of the following is a permissive action of glucocorticoids during stress?

Accepted Answer

Enhancement of catecholamine fat mobilization and maintenance of body temperature

Question 13

Which equation describes the conversion of cortisol to cortisone by 11\beta-hydroxysteroid dehydrogenase?

Accepted Answer

$$	ext{Cortisol} + NAD^+ \xrightarrow{11\beta HSD2} 	ext{Cortisone} + NADH$$

Question 14

Which of the following best explains why the zona glomerulosa can only produce aldosterone and not glucocorticoids or androgens?

Accepted Answer

It lacks 17\alpha-hydroxylase/17,20-desmolase

Question 15

Which of the following is a consequence of excessive glucocorticoid secretion (Cushing’s syndrome)?

Accepted Answer

Centripetal obesity and muscle weakness

Question 16

Which hormone is primarily responsible for stimulating the adrenal cortex to produce glucocorticoids during the second half of fetal development?

Accepted Answer

Adrenocorticotropic hormone (ACTH)

Question 17

Which of the following best describes the effect of glucocorticoids on adipose tissue and skeletal muscle?

Accepted Answer

Catabolic in both tissues

Question 18

Which of the following is a major substrate for steroid biosynthesis in the adrenal cortex?

Accepted Answer

Cholesterol

Question 19

Which equation best represents the negative feedback loop of the HPA axis?

Accepted Answer

$$	ext{CRH} ightarrow 	ext{ACTH} ightarrow 	ext{Cortisol} \dashrightarrow 	ext{CRH}$$

Adrenal Cortex: Structure, Function, and Clinical Relevance

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