AEMCA Practice Exam

What is the primary role of aldosterone in the body?

1. Increase potassium reabsorption

2. Decrease sodium reabsorption

3. Increase sodium re-absorption and cause potassium excretion

4. Stimulate thirst and water intake

The correct answer is: Increase sodium re-absorption and cause potassium excretion

Aldosterone plays a crucial role in regulating electrolyte balance and blood pressure in the body. Its primary function is to increase sodium reabsorption in the kidneys, particularly in the distal tubules and collecting ducts. This action helps to retain sodium in the body, which is essential for maintaining proper fluid balance and blood volume. As sodium is reabsorbed, water follows osmotically, contributing to an increase in blood volume and, consequently, blood pressure. In addition to promoting sodium reabsorption, aldosterone also facilitates the excretion of potassium from the body. This is vital because maintaining appropriate potassium levels is essential for normal cell function, nerve transmission, and muscle contraction. The balance between sodium retention and potassium excretion is critical for overall electrolyte homeostasis and cardiovascular health. The other options do not accurately reflect the primary role of aldosterone. While potassium reabsorption and its effects on thirst and water intake are important physiological processes, they are not the main function associated with aldosterone. This hormone is specifically targeted toward sodium reabsorption and potassium excretion, highlighting its pivotal role in fluid balance and blood pressure regulation.