Which of the following statements is correct?

Options

A. ADH- prevents conversion of angiotensinogen in blood to angiotensin
B. Aldosterone - facilitates water reabsorption
C. ANF- enhances sodium reabsorption
D. Renin - causes vasodilation

Answer

To determine which of the statements is correct, let's analyze each option step by step:

### Step 1: Analyze the First Statement
**Statement:** ADH prevents the conversion of angiotensinogen in blood to angiotensin.

- **Explanation:** ADH (Antidiuretic Hormone) is primarily involved in regulating water reabsorption in the kidneys, particularly in the distal convoluted tubule (DCT) and collecting ducts. It does not have a role in the conversion of angiotensinogen to angiotensin. This conversion is primarily facilitated by renin. Therefore, this statement is **incorrect**.

### Step 2: Analyze the Second Statement
**Statement:** Aldosterone facilitates water reabsorption.

- **Explanation:** Aldosterone is a hormone produced by the adrenal cortex. It promotes the reabsorption of sodium ions in the DCT of the nephron, which indirectly leads to water reabsorption because water follows sodium due to osmotic forces. Thus, this statement is **correct**.

### Step 3: Analyze the Third Statement
**Statement:** ANF enhances sodium reabsorption.

- **Explanation:** Atrial Natriuretic Factor (ANF) is secreted by the heart's right atrium and functions to promote the excretion of sodium (natriuresis) and inhibit renin secretion. Therefore, it does not enhance sodium reabsorption; instead, it promotes sodium excretion. This statement is **incorrect**.

### Step 4: Analyze the Fourth Statement
**Statement:** Renin causes vasodilation.

- **Explanation:** Renin is an enzyme secreted by the juxtaglomerular cells of the kidneys. Its primary function is to convert angiotensinogen into angiotensin I, which is then converted to angiotensin II. Angiotensin II is a potent vasoconstrictor, not a vasodilator. Therefore, this statement is **incorrect**.

### Conclusion
After analyzing all the statements, the only correct statement is:
- **Aldosterone facilitates water reabsorption.**

### Final Answer
The correct statement is: **"Aldosterone facilitates water reabsorption."**

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