The intestines are a pair of organs which form a long continuous tube in the abdomen. They are responsible for extracting water and nutrients from digested food and containing the intestinal bacteria that assist with this process so that they do not enter the bloodstream. The two organs are:
The large intestine or colon, which stretches from the end of the small intestine and is about 4cm in diameter and 3m long. Some nutrients and water are extracted at this point, but for the most part the large intestine prepares digested food to be expelled into the rectum.
If the intestine is pierced by trauma or toxins, intestinal bacteria will seep into the bloodstream, usually resulting in peritonitis.
The intestine can become blocked, occasionally by undigested food, but usually by growths in the intestines, which can be cancerous. This can lead to serious complications and is indicated by severe intestinal pain.