Digestive System

The functions of the digestive system are to digest and absorb foods.

Digestion Digestion is the breakdown of large, insoluble food molecules into small, soluble molecules so that they can be absorbed into the bloodstream. Digestion can be mechanical, for example chewing in the mouth and churning in the stomach to break the food into smaller pieces. Chemical digestion involves the use of special chemicals called enzymes.   These are catalysts which speed up the digestion of large molecules into small ones. The table summarises the types of enzymes and the products of digestion: Enzyme  Where it is produced  Food molecule it acts on  Products of digestion  Amylase  Salivary glands  Pancreas  Wall of small intestine   Starch (a carbohydrate)  Sugars  Protease  Stomach  Pancreas  Wall of small intestine  Proteins  Amino-acids  Lipase  Pancreas  Wall of small intestine   Fats and oils (lipids)  Fatty acids and glycerol Food is digested in the mouth, stomach and small intestine. Hydrochloric acid is also produced in the stomach.