Segments of Henle's loop which is permeable and impermeable to water respectively

Options

A. Ascending Limb, Descending Limb
B. Descending Limb, Ascending Limb
C. Descending Limb, Distal Convoluted Tubule
D. Ascending Limb, Distal Convoluted Tubule

Answer

To answer the question regarding the segments of Henle's loop that are permeable and impermeable to water, we can break down the solution into clear steps:

### Step-by-Step Solution:

1. **Understanding Henle's Loop**:
- The loop of Henle is a U-shaped portion of the nephron, which is the functional unit of the kidney. It consists of two main segments: the descending limb and the ascending limb.

2. **Identifying the Descending Limb**:
- The descending limb of Henle's loop is known to be permeable to water. This means that water can easily move out of this segment into the surrounding interstitial fluid, allowing for the concentration of urine.

3. **Identifying the Ascending Limb**:
- The ascending limb of Henle's loop, on the other hand, is impermeable to water. This segment does not allow water to pass through, which is crucial for the dilution of urine as it reabsorbs electrolytes (like sodium and chloride) without water.

4. **Conclusion**:
- Therefore, the segment of Henle's loop that is permeable to water is the **descending limb**, and the segment that is impermeable to water is the **ascending limb**.

### Final Answer:
- **Permeable to water**: Descending limb of Henle's loop
- **Impermeable to water**: Ascending limb of Henle's loop