Which blood vessel contains the least amount of urea ?

Options

A. Renal vein
B. Renal artery
C. Pulmonary vein
D. Hepatic portal vein

Answer

To determine which blood vessel contains the least amount of urea, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Blood Flow in the Kidneys**:
- Blood enters the kidneys through the **renal artery**. This blood is rich in waste products, including urea.

2. **Filtration Process**:
- Once the blood reaches the kidneys, it undergoes a filtration process in the nephrons. During this process, urea and other waste products are filtered out of the blood.

3. **Reabsorption**:
- While some urea is excreted, the kidneys also reabsorb a portion of water and certain solutes back into the bloodstream. However, the concentration of urea decreases as blood is processed in the kidneys.

4. **Blood Leaving the Kidneys**:
- After filtration and reabsorption, the blood leaves the kidneys through the **renal vein**. This blood has had most of its urea removed, resulting in a lower concentration of urea compared to the blood that entered.

5. **Conclusion**:
- Therefore, the blood vessel that contains the least amount of urea is the **renal vein**.

### Final Answer:
The blood vessel that contains the least amount of urea is the **renal vein**.

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