The bowel is part of the digestive system. It is made up of the small bowel (small intestine) and the large bowel (colon and rectum). The small bowel is longer than the large bowel but it gets its name from the fact it is much narrower than the large bowel.
Cancer is more likely to develop in the large bowel. Small bowel cancer is much less common.
Cancer in the large bowel is called bowel cancer or colorectal cancer. Two out of three bowel cancers develop in the colon and one out of three develop in the rectum.
The digestive system
Your digestive system turns food and liquids into energy that the body can use. The picture below shows the parts of the body that make up the digestive system.
1. Mouth - food and liquids enter the body through the mouth. Chewing breaks down the food
2. Oesophagus - carries the food and liquids to the stomach for digestion
3. Stomach - stores and breaks down the food into a liquid mixture before slowly releasing it into the small bowel.
4. Pancreas - produces enzymes (substances that speed up chemical reactions) that help the body digest fats, proteins and carbohydrates (starchy foods)
5. Small bowel - breaks the food down even further, absorbing the nutrients into the body. Undigested waste moves into the colon.
6. Liver - produces bile, which helps the body absorb fat from food.
7. Gallbladder - stores bile until the body needs it.
8. Large bowel - made up of the colon (8a) and rectum (8b). The body absorbs water from the undigested waste as it moves along the colon towards the rectum. Waste (poo) is stored in the rectum until it passes out of the body.
9. Anus - poo passes through the anus as it leaves the body.
The large bowel
This 3D model lets you look more closely at the parts of the body that make up the large bowel. Click on the numbers to find out more about each part of the large bowel. Click and hold to move the picture 360°.