Blood vessel vessels function to transport blood. In general, arteries and arterioles transport oxygenated blood from the lungs to the body and its organs, and veins and venules transport deoxygenated blood from the body to the lungs. Blood vessels also circulate blood throughout the circulatory system Oxygen (bound to hemoglobin in red blood cells) is the most critical nutrient carried by the blood. In all arteries apart from the pulmonary artery, hemoglobin is highly saturated (95–100%) with oxygen. In all veins apart from the pulmonary vein, the saturation of hemoglobin is about 75%. (The values are reversed in the pulmonary circulation.) In
Superior mesenteric vein 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 of the superior mesenteric vein is quite rare, but a significant cause of mesenteric ischemia and