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

In mammals, which blood vessel would normally carry the largest amount of urea?
  1. Renal vein
  2. Dorsal aorta
  3. Hepatic vein
  4. Hepatic portal vein

Solution

Urea -Ornithine cycle takes place in liver so the hepatic vein leaving liver possesses maximum urea. The  hepatic veins carry oxygen-depleted blood from the liver to the inferior vena cava. 

Harmful nitrogenous waste like ammonia is converted into urea in liver which is later removed by kidneys. Thus, the blood is detoxified of harmful nitrogenous waste.

Asked in: NEET 2016 (Phase 1)

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