The colon (large intestine or large bowel) is an organ of the digestive system that helps remove waste from the body. The colon is the last part of the digestive tract where water, salts, and vitamins are absorbed, and stool formation occurs.
An adult’s colon is about five feet long with a diameter of 2.5 inches. The small intestine is much longer, but the colon has a wider diameter, which is why it’s referred to as the large intestine.
What Is the Function of the Colon?
After food particles are absorbed in the small intestine and nutrients are distributed to the rest of the body the substances that are left over move into the colon.
The functions of the colon include:
- Absorption of water
- Food enters the colon from the small intestine mostly in liquid form (chyme)
- As the food matter passes through the colon, water is absorbed and the material progressively solidifies
- Absorption of the liquid in chyme is important to help solidify the material into feces
- If the materials pass through the colon too quickly, feces will be watery (diarrhea)
- If the materials pass through the colon too slowly, too much water will be absorbed and hard stool will form (constipation)
- Supplying the body with water
- Water is absorbed from chyme
- Production and absorption of vitamins
- Bacteria that reside in the colon help break down of food material that are not digestible
- This breakdown helps with the formation of vitamin K, which helps blood clot
- It also helps produce biotin, and vitamins B1, B2, B6, and B12
- These vitamins are absorbed into the bloodstream through the colon
- The bacteria also produce ions which dissolve in the water in the chyme so when the water is absorbed into the body, the ions are absorbed as well
- The colon also produces byproducts such as the gases carbon dioxide and methane which are what cause flatulence
- Balancing the body’s pH
- The intestinal bacteria involved with the process of fermentation leads to the production of fatty acids, which creates an acidic environment in the colon that can damage the colon walls
- The colon balances the pH by neutralizing the acids which protects the walls of the intestine against damage
- Protecting from infections
- Food materials that enter the colon may contain harmful bacteria which could end up in the bloodstream
- The mucus layer lining the colon prevents this, protecting the body against infection and bacterial diseases
- Antibody production
- Antibodies are part of the body’s immune system and provide immunity against foreign bodies and infections
- The colon produces antibodies