<prompt> Portal Vein is formed by the union of?Superior Mesenteric and Inferior Mesenteric VeinsSuperior Mesenteric and Splenic VeinsSuperior Mesenteric And left renal veinInferior Mesenteric and Splenic Vein  <response>: ANSWER: B Superior Mesenteric and Splenic VeinsREF: Keith L. Moore 4th edition page 142-143The hepatic portal vein, formed by the union of the superior mesenteric and splenic veins, is the main channel of the portal venous system, which collects blood from the abdominal part of the alimentary tract, pancreas, spleen, and most of the gallbladder and carries it to the liverMajor Vessels of the Hepatic Portal System 