Blood vessel prevent backflow as a result of a decrease in blood pressure as the blood passes through the circulatory system. There are various kinds of blood vessels: They are roughly grouped as "arterial" and "venous", determined by whether the blood in it is flowing "away from" (arterial) or "toward" (venous) the heart. The term "arterial blood" is nevertheless used to indicate blood high in oxygen, although the pulmonary artery carries "venous blood" and blood flowing in the pulmonary vein is rich in oxygen. This is because they are carrying the blood to and from the lungs, respectively, to be oxygenated. Blood
Superior mesenteric vein can be fatal. It is estimated that 10-15% of mesenteric ischemia is due to mesenteric thrombosis. Superior mesenteric vein The superior mesenteric vein (SMV) is a blood vessel that drains blood from the small intestine (jejunum and ileum). At its termination behind the neck of the pancreas, the SMV combines with the splenic vein to form the hepatic portal vein. The SMV lies to the right of the similarly named artery, the superior mesenteric artery, which originates from the abdominal aorta. Tributaries of the superior mesenteric vein drain the small intestine, large intestine, stomach, pancreas and appendix and include: Thrombosis