What is permeable for ascending loop of Henle ?

Options

A. Ammonia
B. Glucose
C. `Na^(+)`
D. Water

Answer

**Step-by-Step Solution:**

1. **Understanding the Structure**: The loop of Henle is a U-shaped structure in the nephron of the kidney, consisting of a descending limb and an ascending limb.

2. **Identifying the Ascending Limb**: The ascending loop of Henle is divided into two parts: the thin ascending limb and the thick ascending limb. It is crucial to note that the ascending limb is responsible for the reabsorption of certain ions.

3. **Permeability Characteristics**: The ascending loop of Henle is known to be impermeable to water. This means that water cannot pass through this part of the nephron.

4. **Ion Permeability**: The ascending limb is permeable to various ions, particularly sodium (Na+) and chloride (Cl-). This is important for the process of reabsorption and the concentration of urine.

5. **Evaluating the Options**:
- **Ammonia**: This is not reabsorbed in the ascending loop of Henle; it is primarily handled in the distal convoluted tubule (DCT).
- **Glucose**: Glucose is reabsorbed in the proximal convoluted tubule, not in the ascending loop of Henle.
- **Sodium**: The ascending loop of Henle is permeable to sodium ions, making this option correct.
- **Water**: As established, the ascending loop of Henle is impermeable to water.

6. **Conclusion**: Based on the permeability characteristics of the ascending loop of Henle, the correct answer is that it is permeable to sodium ions.

**Final Answer**: Sodium (C) is the correct answer.

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