Which of the following statement is incorrect?

Options

A. ADH is a vasoconstrictor
B. Aldosterone facilitates wate reabsorption
C. ANF enhance sodium reabsorption
D. ANF causes vasodilation

Answer

To determine which statement is incorrect among the options provided, we will analyze each statement step by step:

### Step 1: Evaluate the first statement - "ADH is a vasoconstrictor."
- **Explanation**: Antidiuretic hormone (ADH), also known as vasopressin, primarily functions to increase water reabsorption in the kidneys, particularly in the collecting ducts. While it can cause vasoconstriction in high concentrations, its primary role is to conserve water and regulate blood osmolarity. Thus, stating that ADH is a vasoconstrictor can be misleading as it is not its primary function.
- **Conclusion**: This statement is **incorrect**.

### Step 2: Evaluate the second statement - "Aldosterone facilitates water reabsorption."
- **Explanation**: Aldosterone is a hormone that promotes sodium reabsorption in the distal convoluted tubule (DCT) of the nephron. As sodium is reabsorbed, water follows osmotically, which indirectly leads to increased water retention. Therefore, it is accurate to say that aldosterone facilitates water reabsorption.
- **Conclusion**: This statement is **correct**.

### Step 3: Evaluate the third statement - "ANF enhances sodium reabsorption."
- **Explanation**: Atrial Natriuretic Factor (ANF) is released by the heart in response to high blood pressure and works to decrease blood volume and pressure by promoting sodium excretion (natriuresis) rather than enhancing sodium reabsorption. Therefore, this statement is misleading.
- **Conclusion**: This statement is **incorrect**.

### Step 4: Evaluate the fourth statement - "ANF causes vasodilation."
- **Explanation**: ANF does indeed promote vasodilation, which helps to lower blood pressure. It counteracts the effects of the renin-angiotensin system (RAS) by causing blood vessels to widen, thus reducing blood pressure.
- **Conclusion**: This statement is **correct**.

### Final Conclusion:
The incorrect statements are:
1. "ADH is a vasoconstrictor."
2. "ANF enhances sodium reabsorption."

Thus, the answer to the question is that the first and third statements are incorrect.

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