When you eat a piece of bread, you don't wake up next day to discover it growing out of your arm! The food we eat has to be broken down into other substances that our bodies can use. This is called digestion. Without digestion, we could not absorb food into our bodies and use it.

Digestion happens in the digestive system, which begins at the mouth and ends at the anus.

After we swallow, our food passes through these organs in turn:

• oesophagus or gullet

• stomach

• small intestine

• large intestine.

Stages of digestion

• Food is digested in the mouth, stomach and small intestine.

• Digested food is absorbed into the bloodstream in the small intestine.

• Excess water is absorbed back into the body in the large intestine.

• Any undigested food passes out of the anus as faeces (pronounced "fee-seez") when we go to the toilet.

Liver and pancreas

The liver and the pancreas play important part in digestion. The liver produces bile, which helps the digestion of fat. The pancreas produces chemicals called digestive enzymes.