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13.40: Large Intestine

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    Liquid to solid. What does this mean?

    Well, that's exactly what the large intestine does. It takes the remains of digested food — that is, food in which all the nutrients and minerals have been removed, and prepares it for elimination.

    The Large Intestine and Its Functions

    From the small intestine, any remaining food wastes pass into the large intestine. The large intestine is a relatively wide tube that connects the small intestine with the anus. Like the small intestine, the large intestine also consists of three parts: the cecum (or caecum), colon, and rectum. 

    Absorption of Water and Elimination of Wastes

    The cecum is the first part of the large intestine, where wastes enter from the small intestine. The wastes are in a liquid state. As they pass through the colon, which is the second part of the large intestine, excess water is absorbed. The remaining solid wastes are called feces. Feces accumulate in the rectum, which is the third part of the large intestine. As the rectum fills, the feces become compacted. After a certain amount of feces accumulate, they are eliminated from the body. A sphincter controls the anus and opens to let feces pass through.

    Bacteria in the Large Intestine

    Trillions of bacteria normally live in the large intestine. Most of them are helpful. In fact, we wouldn’t be able to survive without them. Some of the bacteria produce vitamins, which are absorbed by the large intestine. Other functions of intestinal bacteria include:

    • controlling the growth of harmful bacteria.
    • breaking down indigestible food components.
    • producing substances that help prevent colon cancer.
    • breaking down toxins before they can poison the body.


    • The absorption of water from digestive wastes and the elimination of the remaining solid wastes occur in the large intestine.
    • The large intestine also contains helpful bacteria.


    1. Describe the functions of the three parts of the large intestine.
    2. How do bacteria in the large intestine help keep us healthy?