Blood vessel in mammals that carries relatively least quantity of nitrogenous wastes

Options

A. Hepatic veins
B. Renal vein
C. Renal artery
D. Posterior vena cava

Answer

To solve the question regarding which blood vessel in mammals carries the least quantity of nitrogenous wastes, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Nitrogenous Wastes**:
- In mammals, nitrogenous wastes primarily consist of urea, which is produced from the breakdown of proteins.

2. **Role of the Kidneys**:
- The kidneys are responsible for filtering blood and removing nitrogenous wastes through a process called ultrafiltration. This process forms urine, which contains these wastes.

3. **Blood Vessels Involved**:
- After the kidneys filter the blood, the purified blood is returned to circulation. The blood vessels involved include:
- **Renal Artery**: Carries unfiltered blood to the kidneys.
- **Renal Vein**: Carries filtered (purified) blood away from the kidneys.
- **Hepatic Veins**: Related to the liver, not directly involved in nitrogenous waste removal.
- **Posterior Vena Cava**: A large vein that carries deoxygenated blood to the heart.

4. **Identifying the Correct Vessel**:
- Since the kidneys remove nitrogenous wastes, the blood that leaves the kidneys via the renal vein will have the least amount of nitrogenous wastes compared to the other vessels mentioned.
- The renal artery would carry a higher concentration of nitrogenous wastes as it brings unfiltered blood to the kidneys.

5. **Conclusion**:
- Therefore, the blood vessel that carries the relatively least quantity of nitrogenous wastes in mammals is the **Renal Vein**.

### Final Answer:
- The blood vessel in mammals that carries the relatively least quantity of nitrogenous wastes is the **Renal Vein**.

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