Does the renal vein or does the hepatic portal vein contain more urea?
The kidneys remove urea and other toxic wastes from the blood, forming a dilute solution called urine in the process. The two kidneys have a very extensive blood supply and the whole blood supply passes through the kidneys every 5 minutes, ensuring that waste materials do not build up. The renal artery carries blood to the kidney, while the renal vein carries blood, now with far lower concentrations of urea and mineral ions, away from the kidney. The urine formed passes down the ureter to the bladder. The liver converts ammonia to urea, which is excreted in urine by the kidneys. The blood entering the liver from the portal vein, after being cleaned by the liver, flows into the inferior vena cava via the hepatic veins. Judging by this information i would say it is the Hepatic because it transfers the “stuff” from the liver to the inferior vena cava then it gets to the renal vein which as it says has less urea concentration. With the liver that creates the urea, id say the obvious first
