Final answer:
The hepatic portal vein is never seen IN the liver because it subdivides into smaller vessels at the porta hepatis. This vein is part of the hepatic portal system which delivers blood from the gastrointestinal tract and spleen to the liver for processing.
Step-by-step explanation:
The portal vein you will never see IN the liver is the hepatic portal vein, as once it enters the liver through the porta hepatis, it subdivides into smaller vessels that infiltrate the liver tissue. The hepatic portal vein is a vital part of the hepatic portal system, carrying blood from the gastrointestinal tract and spleen to the liver.
Blood from the hepatic artery and the hepatic portal vein is then processed by the liver, with the resulting blood exiting the liver via the hepatic veins and flowing into the inferior vena cava.