The answer is splenic vein and superior mesenteric vein. To simplify, the hepatic portal vein is made by the union of the splenic vein and the superior mesenteric vein. The hepatic portal vein is one of the utmost significant veins that obtain blood from the body and transfer it to the liver for filtration and treating. This vein is a portion of the hepatic portal system that obtains all of the blood strenuous from the abdominal digestive area also from the pancreas, gallbladder, and spleen.