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The Large Intestines is one of the final stages of the Digestive System.

A large function of this stage is the absorption of water from the remaining undigested material.

The large intestines consist of the Cecum, Colon, Anal Canal, and Rectum.

Undigested material enters from the small intestines. The ileocecal junction is the dividing point of the small and large intestines

The Large intestines on average is 5 feet long. This is much shorter then the small intestines. The diameter of the large intestines is much larger then the small intestines – hence the name.

The wall structure is largely different then the small intestines.

Absorption

–  Occurs for nutrients produced by bacteria found in the colon.
–  Food is not broken down any further in this stage.
–  Salt and Solid wastes are also extracted.
–  The site in which bacteria and other flora helps aid in the fermentation of unabsorbed materials

Locations of the Colon

1.)  Cecum/Appendix

–  First section of colon
–  Appendix develops during embryo stage
–  Not involved in digestion
–  Appendix function is not certain

2.)  Ascending colon

–  Section 1 of Large intestines
–  Connects to Small intestines
–  Runs upwards through abdominal cavity
–  Removes water and key nutrients
–  Unwanted waste continues through system
–  Peristalsis moves wasted through

3.)  Transverse colon

–  Section 2 of Large intestines
–  The portion of colon from hepatic flexure to splenic flexure
–  Hangs off of the stomach.
–  Attached to stomach by a large fold of peritoneum – The Greater Omentum
–  Also connected to abdominal wall on the back side by the Mesentery (tranverse mesocolon)

4.)  Descending colon

–  Section 3 of Large intestines
–  The portion of colon from splenic flxure to Sigmoid.
–  Stores feces
–  2/3 of humans – it is retroperitnoeal.
–  1/3 have a short mesetery
–  Gut flora are very dense in this region

5.)  Sigmoid colon

–  Section 4 of Large intestines
–  Area prior to rectum.
–  S-shaped
–  Walls are muscular and contract to move stool into rectum