Small amount of urea is reabsobed into

Options

A. Cortical interstitium
B. Medullary interstitium
C. DL of Henel's loop
D. Both of the above

Answer

### Step-by-Step Solution:

1. **Understanding Urea Reabsorption**: Urea is a waste product formed from protein metabolism and is primarily excreted through urine. However, some urea is reabsorbed back into the body as it plays a role in various physiological processes.

2. **Identifying the Nephron Structure**: The nephron is the functional unit of the kidney, consisting of several parts: the Proximal Convoluted Tubule (PCT), Loop of Henle, Distal Convoluted Tubule (DCT), and Collecting Duct.

3. **Reabsorption in the Proximal Convoluted Tubule (PCT)**: Approximately 50% of urea is reabsorbed in the PCT. This is the first segment of the nephron where a significant amount of solutes, including urea, is reabsorbed.

4. **Examining Other Nephron Parts**:
- **Loop of Henle**: Primarily involved in water reabsorption, not urea.
- **Collecting Duct**: This structure is crucial for the final concentration of urine and is where a small amount of urea is reabsorbed.

5. **Identifying the Correct Location for Urea Reabsorption**:
- **Cortical Interstitium**: Located in the upper part of the kidney, not significantly involved in urea reabsorption.
- **Medullary Interstitium**: Located deeper in the kidney, near the Loop of Henle and Collecting Duct, where a small amount of urea is indeed reabsorbed.

6. **Conclusion**: The correct answer to the question "Small amount of urea is reabsorbed into" is the **Medullary Interstitium**.

### Final Answer:
**Medullary Interstitium**

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