The hepatic portal vein transports nutrient-rich, deoxygenated blood from the gastrointestinal tract and spleen directly to the liver. This allows the liver to metabolize nutrients, detoxify substances, and process toxins before the blood enters the systemic circulation. Unlike the hepatic artery, the portal vein does not carry oxygenated blood. Clinically, understanding the portal vein’s role is critical during surgeries like partial hepatectomy or portal vein embolization, where maintaining portal flow prevents liver ischemia and ensures proper postoperative liver function.

Reference: Gray's Anatomy, Standring S, 42nd Edition.