What system is the Inferior mesenteric vein part of?

The inferior mesenteric vein is part of the venous system that drains blood from the lower gastrointestinal tract. It specifically collects blood from the rectum, sigmoid colon, and descending colon, and eventually merges with the splenic vein. Together, these veins contribute to the formation of the hepatic portal vein, which transports blood to the liver for processing.