What type of blood does the hepatic portal vein carry to the liver?

The hepatic portal vein is responsible for transporting nutrient-rich venous blood from the gastrointestinal tract and spleen to the liver. This blood is particularly important for the liver's function of processing nutrients absorbed from the digestive system, such as glucose, amino acids, and other metabolites. The liver then metabolizes these nutrients, detoxifies harmful substances, and performs various vital functions essential for maintaining overall metabolic homeostasis.

In the context of the choices provided, nutrient-rich venous blood specifically refers to blood that has a high concentration of the nutrients absorbed from food before being sent to the liver for processing. This distinguishes it from other types of blood present in the circulatory system, such as oxygen-rich blood, which is carried by the arteries from the lungs to the rest of the body, and oxygen-poor blood, which returns to the heart and lungs for reoxygenation. The hepatic portal vein does not carry waste-rich arterial blood; instead, it transports venous blood that has already passed through capillary beds in the intestines, making it rich in the products of digestion.