What is the hepatic portal system?
Portal system is the system which starts with capillaries and end in capillary.
In regular system artery or arteriole breaks in capillaries. But in a portal veins start from capillaries and end in to capillary.
Hepatic portal vein starts with capillaries of alimentary canal. It once again breaks up in capillaries of liver.
It collects end products of digested food to liver. The end products of digested food like free amino acids, monosaccharides and free fatty acids to liver.
In liver the digested food is metabolized. Liver is the main organ of metabolism.
Portal veins is a chordate character.