intestine

The intestine is the long tube in the body that runs from the stomach to the anus. It is a central part of the digestive system, because this is where food keeps moving, nutrients are absorbed, water is taken in, and waste is prepared to leave the body. When people speak in a general way, they may use either intestine for the organ as a whole or intestines for its full system of parts.

This system is divided into two main sections: the small intestine and the large intestine. The small intestine does most of the work of digestion and nutrient absorption. After food leaves the stomach, it enters this long, narrow section, where it is broken down further and useful substances pass into the bloodstream. The large intestine, which includes the colon, is shorter and wider. It absorbs water and salts from what remains and helps form stool before it leaves the body.

The word is most often used in medicine, biology, anatomy, and everyday health talk. You may hear phrases such as intestinal pain, intestinal disease, or intestinal health. It can also appear when people talk about food, since animal intestines are sometimes eaten or used as sausage casings. In a more figurative and less common way, intestinal fortitude means courage or inner strength. In most situations, though, the word simply refers to the digestive passage inside the body.