In mammals, which blood vessel would normally carry largest amount of urea

Options

A. Renal vein
B. Dorsal aorta
C. Hepatic vein
D. Hepatic portal vein

Answer

To determine which blood vessel in mammals carries the largest amount of urea, we can analyze the options provided:

1. **Understanding Urea Production**: Urea is primarily produced in the liver as a result of protein metabolism. Therefore, any blood vessel that is closely associated with the liver is likely to carry significant amounts of urea.

2. **Analyzing the Options**:
- **Option A: Renal Vein**: This vessel carries blood away from the kidneys. While the kidneys filter urea from the blood, they do not produce it.
- **Option B: Dorsal Aorta**: This is a major artery that carries oxygenated blood from the heart to the body. It does not specifically carry urea.
- **Option C: Hepatic Vein**: This vessel carries blood away from the liver. Since urea is produced in the liver, the hepatic vein would carry the largest amount of urea.
- **Option D: Hepatic Portal Vein**: This vein carries blood from the gastrointestinal tract and spleen to the liver. While it does carry substances absorbed from the intestines, it does not carry the largest amount of urea.

3. **Conclusion**: Given that the hepatic vein carries blood away from the liver, where urea is produced, it follows that the hepatic vein would carry the largest amount of urea.

Thus, the correct answer is **Option C: Hepatic Vein**.