Adrenal Cortex and Medulla — MCQs
In a patient diagnosed with pheochromocytoma, what is the appropriate preoperative pharmacological management to control hypertension before surgery?
A patient with a pheochromocytoma is secreting large amounts of norepinephrine into the bloodstream. In a normal individual, this compound is usually released from the adrenal medulla in response to which of the following?
Major hormone secreted by zona reticularis of adrenal cortex -
Which test is essential in a patient with suspected Cushing's syndrome for diagnosis confirmation?
Which of the following best describes the hormonal profile in Cushing's disease?
What is the effect of cortisol on bone metabolism?
All are true about hormone functions except:
Which of the following hormones is released from the posterior pituitary?
A 54-year-old woman appears in your office for a new patient visit. She reports a past medical history of hypertension, which she was told was related to "adrenal gland disease." You recall that Conn syndrome and pheochromocytomas are both conditions affecting the adrenal gland that result in hypertension by different mechanisms. Which areas of the adrenal gland are involved in Conn syndrome and pheochromocytomas, respectively?
Which of the following enzymes is not required for the formation of estradiol?
Adrenal Cortex and Medulla Indian Medical PG Practice Questions and MCQs
Question 1: In a patient diagnosed with pheochromocytoma, what is the appropriate preoperative pharmacological management to control hypertension before surgery?
- A. Phenoxybenzamine and propranolol (Correct Answer)
- B. Propranolol
- C. Nitroglycerine
- D. Phentolamine
Explanation: ***Phenoxybenzamine and propranolol*** - **Phenoxybenzamine** (an **irreversible** non-selective **alpha-blocker**) is initiated first to prevent hypertensive crises during surgery by blocking the effects of catecholamines on blood vessels. - **Propranolol** (a **beta-blocker**) is added after adequate alpha-blockade to control **tachycardia** and arrhythmias, as blocking only alpha-receptors can lead to unopposed beta-adrenergic stimulation. *Phentolamine (short-acting alpha blocker)* - While **phentolamine** is an alpha-blocker, it is typically used for **intraoperative management** of hypertensive crises or for short-term control, not as the primary preoperative preparation. - It is a **reversible** blocker and does not provide the sustained, robust alpha-blockade required for safe preoperative management of pheochromocytoma. *Propranolol (beta-blocker)* - **Beta-blockers** alone should **never be started first** in pheochromocytoma because blocking beta-2 receptors (which mediate vasodilation) in the presence of high circulating catecholamines can lead to **unopposed alpha-adrenergic vasoconstriction**, causing a dangerous hypertensive crisis. - It is only added after adequate alpha-blockade has been achieved to manage **tachycardia**. *Nitroglycerine (vasodilator)* - **Nitroglycerine** is primarily a **venodilator** and is used to relieve angina or manage acute hypertensive emergencies, not for the chronic preoperative management of pheochromocytoma. - It does not address the underlying pathophysiology of excessive catecholamine release and can lead to reflex **tachycardia**.
Question 2: A patient with a pheochromocytoma is secreting large amounts of norepinephrine into the bloodstream. In a normal individual, this compound is usually released from the adrenal medulla in response to which of the following?
- A. Acetylcholine (Correct Answer)
- B. Normetanephrine
- C. Metanephrine
- D. Epinephrine
Explanation: ***Acetylcholine*** - **Acetylcholine** is the primary neurotransmitter released by **preganglionic sympathetic fibers** that innervate the adrenal medulla. - Upon binding to **nicotinic receptors** on chromaffin cells, acetylcholine stimulates the release of catecholamines, including norepinephrine and epinephrine, into the bloodstream. *Normetanephrine* - **Normetanephrine** is a metabolite of **norepinephrine**, not a hormone that triggers its release. - It is formed by the action of **catechol-O-methyltransferase (COMT)** on norepinephrine. *Metanephrine* - **Metanephrine** is a metabolite of **epinephrine**, not a substance that stimulates catecholamine release from the adrenal medulla. - Like normetanephrine, it is also formed by the action of **COMT**. *Epinephrine* - **Epinephrine** (adrenaline) is a hormone primarily produced and released by the **adrenal medulla**, alongside norepinephrine. - While both are catecholamines, epinephrine does not trigger its own release or the release of norepinephrine in this context; instead, their release is stimulated by acetylcholine.
Question 3: Major hormone secreted by zona reticularis of adrenal cortex -
- A. Mineralcorticoids
- B. Androgens (Correct Answer)
- C. Aldosterone
- D. Glucocorticoids
Explanation: ***Androgens*** - The **zona reticularis** is the innermost layer of the adrenal cortex and is primarily responsible for the production of **adrenal androgens**, mainly dehydroepiandrosterone (DHEA) and androstenedione. - These androgens contribute to secondary sexual characteristics, particularly in females, and can be converted to more potent androgens or estrogens in peripheral tissues. *Mineralcorticoids* - **Mineralcorticoids**, primarily **aldosterone**, are secreted by the **zona glomerulosa**, the outermost layer of the adrenal cortex. - They regulate **electrolyte balance** and **blood pressure** through their actions on the kidneys. *Aldosterone* - **Aldosterone** is the main mineralcorticoid and is produced in the **zona glomerulosa**, not the zona reticularis. - Its primary role is to promote **sodium reabsorption** and **potassium excretion** in the renal tubules. *Glucocorticoids* - **Glucocorticoids**, such as **cortisol**, are primarily produced in the **zona fasciculata**, the middle layer of the adrenal cortex. - They are involved in **stress response**, **glucose metabolism**, and **immune system regulation**.
Question 4: Which test is essential in a patient with suspected Cushing's syndrome for diagnosis confirmation?
- A. Serum aldosterone
- B. Serum renin
- C. Plasma ACTH
- D. 24-hour urine cortisol (Correct Answer)
Explanation: ***24-hour urine cortisol*** - This test measures the **total amount of cortisol excreted** in the urine over a 24-hour period, reflecting the average daily cortisol production. [1] - An **elevated 24-hour urine free cortisol** is a primary diagnostic test to confirm hypercortisolism in suspected Cushing's syndrome. [1] *Serum aldosterone* - This test is primarily used in the diagnosis of **hyperaldosteronism**, such as Conn's syndrome, which causes hypertension and hypokalemia. - While related to the adrenal glands, **aldosterone levels are not directly used to diagnose Cushing's syndrome**. *Serum renin* - This test is part of the workup for **hypertension** and is used in conjunction with aldosterone to assess the **renin-angiotensin-aldosterone system**. - It is **not a direct or essential test** for the diagnosis of Cushing's syndrome. *Plasma ACTH* - While **plasma ACTH** is crucial for differentiating between different causes of Cushing's syndrome (e.g., ACTH-dependent vs. ACTH-independent), it is **not the initial diagnostic test to confirm the presence of hypercortisolism**. [2] - **Confirmation of cortisol excess** typically precedes ACTH measurement to determine the etiology. [2]
Question 5: Which of the following best describes the hormonal profile in Cushing's disease?
- A. Decreased ACTH and decreased cortisol levels
- B. Increased ACTH and decreased cortisol levels
- C. Increased catecholamines
- D. Increased ACTH and increased cortisol levels (Correct Answer)
Explanation: ***Increased ACTH and increased cortisol levels*** - **Cushing's disease** is caused by an **ACTH-producing pituitary adenoma** [1], leading to excessive stimulation of the adrenal glands. - This results in **elevated ACTH** secretion, which then drives the adrenal glands to produce **excessive cortisol** [3]. *Decreased ACTH and decreased cortisol levels* - This profile typically indicates **adrenal insufficiency**, such as **Addison's disease**, where the adrenal glands fail to produce enough cortisol, and the pituitary tries to compensate (leading to high ACTH initially) or in central adrenal insufficiency where both ACTH and cortisol are low. - It describes a state of **cortisol deficiency**, which is the opposite of the hypercortisolism seen in Cushing's disease. *Increased ACTH and decreased cortisol levels* - This scenario suggests **primary adrenal insufficiency** (Addison's disease), where the adrenal glands cannot produce sufficient cortisol despite high stimulation from the pituitary gland. - The adrenal glands are unable to respond to the elevated ACTH by producing more cortisol. *Increased catecholamines* - **Elevated catecholamine levels** (epinephrine and norepinephrine) are characteristic of **pheochromocytoma** [2], a tumor of the adrenal medulla. - This condition is distinct from Cushing's disease, which involves excessive cortisol production, not catecholamines.
Question 6: What is the effect of cortisol on bone metabolism?
- A. Decreased bone matrix (Correct Answer)
- B. Increases calcium absorption
- C. Stimulates osteoblast activity
- D. Increased bone matrix
Explanation: ***Decreased bone matrix*** - Cortisol **inhibits osteoblast activity** and **promotes osteoblast apoptosis**, leading to reduced production of bone matrix components like collagen - It also **increases osteoclast activity**, further contributing to bone breakdown and resulting in a net decrease in bone matrix - This mechanism is the primary cause of **glucocorticoid-induced osteoporosis** *Increases calcium absorption* - Cortisol actually **decreases intestinal calcium absorption** by reducing the sensitivity of the intestines to vitamin D - This effect contributes to **negative calcium balance** and exacerbates bone loss *Stimulates osteoblast activity* - Cortisol has an **inhibitory effect on osteoblast differentiation and function**, leading to reduced bone formation - This suppression of osteoblasts is the opposite of this option and directly contributes to weaker bones *Increased bone matrix* - This is incorrect as cortisol leads to **net bone loss**, not an increase, by inhibiting bone formation and accelerating bone resorption - An increase in bone matrix would require enhanced osteoblast activity, which is the opposite of cortisol's effect
Question 7: All are true about hormone functions except:
- A. Cortisol regulates plasma volume (Correct Answer)
- B. Thyroid hormones regulate metabolism
- C. ADH regulates blood osmolality
- D. Insulin regulates blood glucose
Explanation: ***Cortisol regulates plasma volume*** - While cortisol plays a role in fluid balance by influencing **renal perfusion** and the action of other hormones like ADH, its primary role is not the direct regulation of plasma volume. - **Aldosterone** is the primary hormone directly responsible for regulating plasma volume through its effects on sodium and water reabsorption in the kidneys. *Thyroid hormones regulate metabolism* - **Thyroid hormones** (T3 and T4) are crucial for regulating the body's metabolic rate, influencing factors like energy production, protein synthesis, and cellular oxygen consumption. - They impact the metabolism of **carbohydrates, fats, and proteins**, affecting nearly every cell in the body. *ADH regulates blood osmolality* - **Antidiuretic hormone (ADH)**, also known as vasopressin, primarily regulates blood osmolality by controlling the reabsorption of water in the renal collecting ducts. - It increases the permeability of collecting ducts to water, thus concentrating urine and **reducing plasma osmolality** when it's high. *Insulin regulates blood glucose* - **Insulin** is a key hormone produced by the pancreas that regulates blood glucose levels by facilitating the uptake of glucose into cells for energy or storage. - It plays a crucial role in lowering blood glucose after meals by promoting **glucose utilization** and inhibiting glucose production by the liver.
Question 8: Which of the following hormones is released from the posterior pituitary?
- A. Luteinizing hormone
- B. Growth hormone
- C. Antidiuretic hormone (Correct Answer)
- D. ACTH
Explanation: ***Antidiuretic hormone*** - The **posterior pituitary** (neurohypophysis) stores and releases **antidiuretic hormone (ADH)** and oxytocin. - ADH, also known as **vasopressin**, is synthesized in the **hypothalamus** and transported to the posterior pituitary for release. *Luteinizing hormone* - **Luteinizing hormone (LH)** is released from the **anterior pituitary** in response to gonadotropin-releasing hormone (GnRH) from the hypothalamus. - LH plays a crucial role in **reproduction**, triggering ovulation in females and testosterone production in males. *Growth hormone* - **Growth hormone (GH)** is synthesized and secreted by the **anterior pituitary gland**. - Its release is regulated by **growth hormone-releasing hormone (GHRH)** and **somatostatin** from the hypothalamus. *ACTH* - **Adrenocorticotropic hormone (ACTH)** is produced and secreted by the **anterior pituitary gland**. - ACTH stimulates the **adrenal cortex** to release cortisol, regulating stress responses and metabolism.
Question 9: A 54-year-old woman appears in your office for a new patient visit. She reports a past medical history of hypertension, which she was told was related to "adrenal gland disease." You recall that Conn syndrome and pheochromocytomas are both conditions affecting the adrenal gland that result in hypertension by different mechanisms. Which areas of the adrenal gland are involved in Conn syndrome and pheochromocytomas, respectively?
- A. Medulla; zona reticularis
- B. Zona fasciculata; zona reticularis
- C. Zona glomerulosa; medulla (Correct Answer)
- D. Zona glomerulosa; zona fasciculata
- E. Zona fasciculata; medulla
Explanation: ***Zona glomerulosa; medulla*** - **Conn syndrome** (primary hyperaldosteronism) is caused by excessive **aldosterone** production, which occurs in the **zona glomerulosa** of the adrenal cortex [1]. - **Pheochromocytoma** is a tumor of the **adrenal medulla** that produces excessive **catecholamines** (epinephrine and norepinephrine) [2]. *Medulla; zona reticularis* - The **adrenal medulla** produces catecholamines [2], associated with pheochromocytoma, but the **zona reticularis** produces androgens [1], not implicated in Conn syndrome. - Conn syndrome involves the **zona glomerulosa**, not the zona reticularis. *Zona fasciculata; zona reticularis* - The **zona fasciculata** produces glucocorticoids (e.g., cortisol) [1], and the **zona reticularis** produces androgens. Neither is primarily associated with Conn syndrome or pheochromocytoma. - Conn syndrome is linked to the **zona glomerulosa**, and pheochromocytoma to the **medulla**. *Zona glomerulosa; zona fasciculata* - While the **zona glomerulosa** is correctly associated with Conn syndrome (aldosterone production) [1], the **zona fasciculata** produces glucocorticoids, not catecholamines, and is therefore not involved in pheochromocytoma. - Pheochromocytomas originate in the **adrenal medulla**. *Zona fasciculata; medulla* - The **zona fasciculata** produces glucocorticoids, not aldosterone, so it is not associated with Conn syndrome. - The **adrenal medulla** is correctly associated with pheochromocytoma, but this option incorrectly links Conn syndrome to the zona fasciculata.
Question 10: Which of the following enzymes is not required for the formation of estradiol?
- A. Aromatase
- B. 3β-hydroxysteroid dehydrogenase
- C. 11β-hydroxylase (Correct Answer)
- D. 17α-hydroxylase
Explanation: ***11β-hydroxylase*** - This enzyme is crucial for the **synthesis of cortisol** and **aldosterone** within the adrenal cortex, converting 11-deoxycortisol to cortisol and 11-deoxycorticosterone to corticosterone. - It plays no direct role in the synthesis pathway of **estrogen**, specifically estradiol, which is synthesized from androgens. *3β-hydroxysteroid dehydrogenase* - This enzyme is required for multiple steps in steroidogenesis, including the conversion of **pregnenolone to progesterone** and **DHEA to androstenedione**, both of which are precursors to estrogens like estradiol. - Its activity is essential for moving from **Δ5 steroids** to **Δ4 steroids**, an early and critical step in androgen and subsequent estrogen synthesis. *Aromatase* - **Aromatase (CYP19A1)** is the enzyme directly responsible for converting androgens (**androstenedione and testosterone**) into estrogens (**estrone and estradiol**, respectively). - It catalyzes the **aromatization of the A-ring** of the steroid structure, a defining step in estrogen synthesis. *17α-hydroxylase* - This enzyme (CYP17A1) is involved in crucial steps leading up to estrogen synthesis, including the conversion of **progesterone to 17α-hydroxyprogesterone** and **pregnenolone to 17α-hydroxypregnenolone**. - Its activity is necessary for the formation of **androgens** (like DHEA and androstenedione), which are direct precursors for estrogen synthesis.
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