Large Intestine (Introduction)

Knowledge of the the large intestine is required for introductory courses in anatomy & physiology, human biology, and zoology. This simple description of the large intestine is useful for school pupils, A-Level Human Biology, and ITEC Anatomy & Physiology students. It may also be helpful to students of other health science subjects such as nursing, diet and nutrition and similar. This follows the pages about the small intestine.

The large intestine is part of the digestive system and is located in the lower area of the abdomen within the large membrane known as the peritoneum (which has 2 layers separated by a small amount of liquid, enabling the organs contained within it to move freely over and around each other). The large intestines begin at the bottom of the abdomen, where material is received from the ileum, which is the final part of the small intestine.

The large intestine consists of the cecum (sometimes written caecum), the colon (which consists of 4 parts), and the rectum. Hence, in common with the small intestines, the large intestines can also be described in three parts:

1. The cecum is the first part of the large intestine and so receives material from the ileum.
   
   
2. The second part of the large intestines is the colon, which initially rises upwards within the abdomen (ascending colon), then moves across the body beneath the liver and stomach (transverse colon), then finally passes downwards back to the lower abdomen (descending colon).
   
   
3. The third part of the large intestines is the rectum which is located in the approx. centre of the lower abdomen.

The large intestine can be described using diagrams - see the simple diagram of the large intestine below to understand the flow of material through the large intestine. For more detail see the labelled diagram of the large intestine.

Simple Diagram of the Large Intestine (main structures and flow only)

This diagram is interactive - click on a text label (indicated in green) for more information about that topic, on another page.

See also the small intestine and a more detailed diagram of the large intestine.