The intestines are part of the digestive system. There are two parts of the intestine: the small intestine and the large intestine. The large intestine is made up of the colon, the rectum, and the anus.
When food is ingested, it goes through the esophagus and into the stomach, where digestion begins. From here, it goes into the small intestine, where its essential nutrients are absorbed by the body. Food then goes into the colon, where water is absorbed. The remaining waste products (feces) go into the rectum, where they remain until they exit the body through the anus.
The colon is divided into four sections.
- Ascending colon
The first part of the colon begins in the lower right part of your abdomen, just after the small intestine. It goes up toward the right side of the abdomen.
- Transverse colon
This section crosses from the right side to the left of the abdomen.
- Descending colon
This section goes down the left side of the abdomen.
- Sigmoid colon
The last part of the colon is an s-shaped curve that joins up with the rectum.
The walls of the colon are made up of layers of body tissue. Most cancers of the colon start in the inner lining of the intestine and develop from small growths called polyps.