The Digestive System

Food passes along from the mouth to the oesophagus, stomach, small intestine and large intestine. Digestion involves the physical break down of food using teeth, tongue and stomach muscles churning. It also involves chemical breakdown using enzymes

This all results in large insoluble molecules being broken into small soluble ones which can be absorbed in the small intestine.

Stages of digestion

Different things happen to food as it passes through the digestive system:

• 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 when we go to the toilet

Liver and pancreas

The liver and the pancreas play an important part in digestion. The liver produces bile, which helps the digestion of lipids (fats and oil). The pancreas produces biological catalysts called digestive enzymeswhich speed up the digestive reactions.

Modelling the digestive system

This is a common experiment used to model the digestive system and should help you…