Which substance is transported to the liver by the hepatic portal vein along with nutrients?

Which substance is transported to the liver by the hepatic portal vein along with nutrients?

• A. Oxygen
• B. Hormones
• C. Amino acids
• D. Carbon dioxide

Answer: (C)

The key idea is that the hepatic portal vein brings blood from the digestive organs to the liver, carrying nutrients absorbed from the gut. Along with these nutrients, amino acids—the components of proteins—are transported in this portal blood so the liver can process them for protein synthesis or energy metabolism. Oxygen, on the other hand, is delivered mainly by the hepatic artery, not via the portal vein. Hormones can travel through the bloodstream, but the defining feature of the portal system is delivering absorbed nutrients, including amino acids. Carbon dioxide is a waste product carried from tissues to the lungs, not transported to the liver by the portal vein.

The key idea is that the hepatic portal vein brings blood from the digestive organs to the liver, carrying nutrients absorbed from the gut. Along with these nutrients, amino acids—the components of proteins—are transported in this portal blood so the liver can process them for protein synthesis or energy metabolism. Oxygen, on the other hand, is delivered mainly by the hepatic artery, not via the portal vein. Hormones can travel through the bloodstream, but the defining feature of the portal system is delivering absorbed nutrients, including amino acids. Carbon dioxide is a waste product carried from tissues to the lungs, not transported to the liver by the portal vein.