Question

Diuresis is prevented by:

• A. Renin from JG cell via switching off the osmoreceptors
• B. ANF from adrenal medulla
• C. Aldosterone from adrenal medulla
• D. Vasopressin from Neurohypophysis

Answer 1

The Correct Option is D

To understand why the correct answer is "Vasopressin from Neurohypophysis," we need to explore the roles of the options given in the context of diuresis.

1. Renin from JG cell via switching off the osmoreceptors:

   Renin is an enzyme secreted by the juxtaglomerular (JG) cells of the kidney. It helps regulate blood pressure through the renin-angiotensin-aldosterone system. However, it does not directly prevent diuresis by affecting osmoreceptors.

2. ANF from adrenal medulla:

   Atrial Natriuretic Factor (ANF) is released by the heart's atria, not the adrenal medulla. ANF promotes diuresis by causing the excretion of sodium and water, thereby increasing urine output, which is the opposite of preventing diuresis.

3. Aldosterone from adrenal medulla:

   Aldosterone is actually produced by the adrenal cortex, not the medulla. It helps retain sodium in the body and excretes potassium. While it contributes to water retention, its primary role is the regulation of sodium and potassium, not directly preventing diuresis.

4. Vasopressin from Neurohypophysis:

   Also known as Antidiuretic Hormone (ADH), vasopressin is released from the posterior pituitary gland, also called the neurohypophysis. It directly prevents diuresis by increasing water reabsorption in the kidneys, thus reducing urine volume. This action is crucial for maintaining body water balance.

In summary, the main hormone responsible for preventing diuresis is Vasopressin from Neurohypophysis. It acts by promoting water reabsorption in the kidneys, thus concentrating urine and reducing its volume.