The Large Intestine

The large intestine is the final part of the digestive system. It is responsible for absorbing water from the undigested food and preparing it to be removed from the body as waste. It is about 1.5 meters long (5 feet) and wider than the small intestine but much shorter.

1. Absorption of Water: The main function of the large intestine is to absorb water and minerals from the undigested food that enters from the small intestine. This process prevents dehydration by reclaiming water.
2. Formation of Waste Material: After absorbing water, the undigested material becomes more solid and forms faeces. Faeces contain fibre, bacteria, and waste products that cannot be digested.
3. Role of the Appendix: A small, tube-like structure called the appendix is attached to the first part of the large intestine. The appendix has no significant role in digestion, but it can sometimes become infected (causing appendicitis).
4. Elimination of Waste: The waste material is stored temporarily in the rectum. It is then expelled from the body through the anus during the process of defecation (passing stool).

• The large intestine has a wider diameter than the small intestine.
• It is the terminal part of the alimentary canal.
• It is divided into three main parts: caecum, colon and rectum.
• The rectum opens to the outside through the anus.
• Only minimal digestion occurs here, but water and electrolytes are absorbed efficiently.