<P> The transverse colon is encased in peritoneum, and is therefore mobile (unlike the parts of the colon immediately before and after it). </P> <P> The proximal two - thirds of the transverse colon is perfused by the middle colic artery, a branch of the superior mesenteric artery (SMA), while the latter third is supplied by branches of the inferior mesenteric artery (IMA). The "watershed" area between these two blood supplies, which represents the embryologic division between the midgut and hindgut, is an area sensitive to ischemia . </P> <P> The descending colon is the part of the colon from the splenic flexure to the beginning of the sigmoid colon . One function of the descending colon in the digestive system is to store feces that will be emptied into the rectum . It is retroperitoneal in two - thirds of humans . In the other third, it has a (usually short) mesentery . The arterial supply comes via the left colic artery . The descending colon is also called the distal gut, as it is further along the gastrointestinal tract than the proximal gut . Gut flora are very dense in this region . </P> <P> The sigmoid colon is the part of the large intestine after the descending colon and before the rectum . The name sigmoid means S - shaped (see sigmoid; cf . sigmoid sinus). The walls of the sigmoid colon are muscular, and contract to increase the pressure inside the colon, causing the stool to move into the rectum . </P>

The colon (large intestine) is the site where most nutrients are absorbed