Which of the following statements is correct ?

Options

A. The ascending limb of loop of Henle is impermeable to water
B. The descending limb of loop of Henle is impermeable to water
C. The ascending limb of loop of Henle is permeable to water
D. The descending limb of loop of Henle is permeable to electrolytes

Answer

To determine which statement is correct regarding the loop of Henle in the nephron, we need to analyze each option based on our understanding of its structure and function.

### Step-by-Step Solution:

1. **Understanding the Loop of Henle**:
- The loop of Henle consists of two limbs: the descending limb and the ascending limb.
- The descending limb is primarily responsible for the reabsorption of water.
- The ascending limb is primarily responsible for the reabsorption of electrolytes.

2. **Analyzing the Options**:
- **Option A**: "Ascending limb of loop of Henle is impermeable to water."
- This statement is correct. The ascending limb does not allow water to pass through, making it impermeable to water.

- **Option B**: "Descending limb of loop of Henle is impermeable to water."
- This statement is incorrect. The descending limb is permeable to water, allowing for water reabsorption.

- **Option C**: "Ascending limb of loop of Henle is permeable to water."
- This statement is incorrect. The ascending limb is impermeable to water.

- **Option D**: "Descending limb of loop of Henle is permeable to electrolytes."
- This statement is also incorrect. The descending limb is permeable to water but not to electrolytes.

3. **Conclusion**:
- The only correct statement among the options is **Option A**: "Ascending limb of loop of Henle is impermeable to water."

### Final Answer:
The correct statement is **Option A**: "Ascending limb of loop of Henle is impermeable to water."

---