This set of Molecular Endocrinology Multiple Choice Questions & Answers (MCQs) focuses on “Metabolic Role of Aldosterone”.
1. What is the role of aldosterone in tubular reabsorption?
a) Increase reabsorption of sodium
b) Decrease reabsorption of sodium
c) Increase reabsorption of calcium
d) Increase reabsorption of potassium
View Answer
Explanation: Increasing the rate of tubular reabsorption of Na is the most significant result of aldosterone and other mineralocorticoids. Sodium is reabsorbed to its full capacity from the renal tubules.
2. What is the role of aldosterone in potassium metabolism of the body?
a) Decreases renal excretion of potassium
b) Increases renal excretion of potassium
c) Increases tubular reabsorption of potassium
d) Blocks tubular reabsorption of potassium
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Explanation: In the renal distal tubules and accumulating ducts aldosterone increase the loss of potassium. This can arise from the removal of potassium in exchange for reabsorbed sodium. Usually, aldosterone in your blood combines sodium and potassium. But too much of this hormone will cause potassium to be lost and sodium to be retained.
3. Which mineral metabolic disorder is related to hypokalaemia disease?
a) Sodium
b) Calcium
c) Potassium
d) Chlorine
View Answer
Explanation: The urinary depletion of potassium lowers its level in ECF, resulting in ‘hypokalaemia.’ Therefore, there would be a gross reduction in potassium (K+) ions at the same time as Na+ and Cl– ions are increased in ECF.
4. The lack of aldosterone can cause loss of as much as 12 grams of sodium in the urine per day.
a) True
b) False
View Answer
Explanation: A complete lack of aldosterone secretion will result in a daily loss of up to 12 g of Na in the urine. This is an amount equal to 1/7th of all the sodium in the whole body. In a rare disorder called Addison’s disease, low levels of aldosterone are observed.
5. Aldosterone can also increase the reabsorption of chlorine.
a) True
b) False
View Answer
Explanation: Aldosterone is a mineralocorticoid hormone synthesized from the zona fasciculata cells of the adrenal cortex. Main role of aldosterone is the sodium and water retention and potassium elimination. However, in addition to this function, aldosterone can also increase the reabsorption of chlorine from the renal tubules.
6. What mineral condition leads to muscle paralysis?
a) Low sodium concentration
b) Low potassium concentration
c) High potassium concentration
d) Low chlorine concentration
View Answer
Explanation: Paralysis is a lack of strength in a portion of the body and control over a muscle or group of muscles. Often the low concentration of K+ contributes to muscle paralysis. This is caused by nerve and muscle fiber hyperpolarization, which inhibits the transfer of action potential.
7. Which mineralocorticoid hormone secretion leads to alkalosis?
a) Aldosterone
b) Cortisol
c) Corticosterone
d) Cortisone
View Answer
Explanation: One bicarbonate ion enters the ECF with each sodium ion reabsorption by hydrogen ion exchange through the action of aldosterone, that transfers the reaction to the alkaline side. Thus, increased aldosterone secretion facilitates alkalosis, while acidosis is produced by its decreased secretion.
8. What is the effect of aldosterone in fluid volume?
a) Decrease water excretion
b) Increase water excretion
c) Decrease water reabsorption
d) Increase water reabsorption
View Answer
Explanation: The quantity of sodium, chlorine, and bicarbonate ions in the ECF is significantly increased by mineralocorticoids, increasing the electrolyte concentration in the ECF. In exchange, this boosts water reabsorption from the tubules.
9. What is the effect of aldosterone in blood volume?
a) Increase in blood volume
b) Decrease in blood volume
c) Maintains the blood volume
d) Decrease in plasma volume
View Answer
Explanation: In the early part of an increase in ECF volume, the plasma volume rises nearly proportionally. Hence a slight to moderate rise in blood volume is one of the results of elevated aldosterone secretion.
10. Which hormone induces the secretion of hepatic aldosterone?
a) Cortisol
b) Androstenedione
c) Corticosterone
d) Androgens
View Answer
Explanation: It has been reported recently that significant quantities of aldosterone in the liver are formed from ‘androstenedione. ‘But this could have no biological peripheral function because before reaching the liver, it may be inactivated by reduction and conjugation.
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