AEMCA Practice Exam

What primarily controls reabsorption in the kidneys?

1. Cortisol and insulin

2. Aldosterone and ADH

3. Renin and angiotensin

4. Natriuretic peptides

The correct answer is: Aldosterone and ADH

The primary control of reabsorption in the kidneys is significantly influenced by aldosterone and antidiuretic hormone (ADH). Aldosterone, a steroid hormone produced by the adrenal glands, plays a crucial role in regulating the sodium balance in the body. It promotes sodium reabsorption in the distal convoluted tubules and collecting ducts of the nephron, which enhances water retention and consequently increases blood volume and blood pressure. ADH, also known as vasopressin, is released by the posterior pituitary gland in response to changes in blood osmolarity or blood volume. It facilitates the reabsorption of water in the kidneys by increasing the permeability of the collecting ducts, allowing more water to be absorbed back into the bloodstream. This mechanism intensifies the effect of aldosterone, leading to a more significant increase in water and sodium retention. The combination of these two hormones allows the kidneys to finely tune the reabsorption of both water and electrolytes, making the body more efficient in balancing fluid and electrolyte homeostasis. This regulatory function is essential for maintaining overall body fluid balance and blood pressure regulation. Therefore, aldosterone and ADH are fundamental to the process of reabsorption in the kidneys, helping the body respond appropriately to changes in