aldosterone

Question 1

Q

Answer 1

A

Question 2

What is the primary physiological function of aldosterone?

Answer 2

To increase blood pressure and blood volume by promoting sodium (and thus water) reabsorption and potassium excretion in the kidneys.

Question 3

Where is aldosterone produced and secreted from?

Answer 3

The zona glomerulosa of the adrenal cortex.

Question 4

What is the primary trigger for aldosterone release?

Answer 4

1. Angiotensin II (via the Renin-Angiotensin-Aldosterone System - RAAS) 2. Hyperkalemia (elevated K+).

Question 5

What is the mechanism of action of aldosterone?

Answer 5

It binds to intracellular mineralocorticoid receptors in the principal cells of the renal collecting duct, leading to increased synthesis of Na+ channels (ENaC) and Na+/K+ ATPase pumps.

Question 6

What are the key target cells for aldosterone in the kidney?

Answer 6

The principal cells of the cortical collecting duct.

Question 7

What are the main effects of aldosterone on the kidney?

Answer 7

1. Increased Na+ reabsorption 2. Increased K+ secretion 3. Increased H+ secretion (acidifies urine).

Question 8

How does aldosterone affect blood pH?

Answer 8

It promotes a metabolic alkalosis by secreting H+ ions in the intercalated cells of the collecting duct.

Question 9

What is the relationship between Aldosterone and ANP (Atrial Natriuretic Peptide)?

Answer 9

They are antagonists. ANP inhibits aldosterone secretion to promote sodium and water excretion

Question 10

What is the effect of hyperaldosteronism (e.g.

Answer 10

Conn’s syndrome) on serum electrolyte levels?

Question 11

What is the effect of hypoaldosteronism (e.g.

Answer 11

Addison’s disease) on serum electrolyte levels?

Question 12

What is the role of Aldosterone in the “Pressure-Natriuresis” mechanism?

Answer 12

Chronic high aldosterone initially increases sodium reabsorption

Question 13

What is the most potent physiological stimulator of aldosterone secretion?

Answer 13

An increase in plasma Potassium (K+) concentration.

Question 14

How does the Juxtaglomerular (JG) Apparatus sense the need for aldosterone release?

Answer 14

The JG cells sense decreased renal perfusion pressure and release Renin

Question 15

What is the effect of Aldosterone on urine osmolarity?

Answer 15

Decreases urine osmolarity (makes urine more dilute) because it reabsorbs solute (NaCl) without water

Question 16

Which enzyme deficiency in the adrenal cortex would lead to a shunting of precursors towards aldosterone production?

Answer 16

21-Beta Hydroxylase deficiency. This shunts precursors to the androgen pathway

Question 17

Q

Answer 17

A

Question 18

A 45-year-old female presents with muscle weakness

Answer 18

fatigue

Question 19

A patient with congestive heart failure is treated with an ACE inhibitor. This drug will lead to a decrease in the production of which of the following hormones?

Answer 19

Angiotensin II. A decrease in Angiotensin II will subsequently lead to a decrease in Aldosterone secretion, reducing sodium reabsorption and blood volume.

Question 20

A 55-year-old man with chronic renal failure has hyperkalemia. Which of the following hormonal changes is expected in this patient?

Answer 20

Increased Aldosterone secretion. Hyperkalemia is a potent direct stimulator of aldosterone release from the adrenal cortex to promote potassium excretion.

Question 21

A patient presents with hyponatremia

Answer 21

hyperkalemia

Question 22

Which of the following drugs directly antagonizes the effect of aldosterone in the distal convoluted tubule and collecting duct?

Answer 22

Spironolactone (a potassium-sparing diuretic). It is a direct competitive antagonist of the mineralocorticoid receptor.

Question 23

In the Renin-Angiotensin-Aldosterone System (RAAS)

Answer 23

what is the primary stimulus for renin release from the juxtaglomerular cells?

Question 24

A patient’s blood work shows high aldosterone and high renin levels. This pattern is most consistent with which of the following?

Answer 24

Secondary Hyperaldosteronism (e.g., Renal Artery Stenosis, CHF, Cirrhosis). The high renin is driving the high aldosterone.

Question 25

What is the direct effect of Aldosterone on the Na+/K+ ATPase pump in the principal cells of the renal collecting duct?

Answer 25

It increases the synthesis and activity of the Na+/K+ ATPase pump on the basolateral membrane, pumping Na+ out and K+ into the blood.