Digestion starts when the food enters our mouth and we start chewing it. Chewing breaks the food into smaller pieces so that it can be swallowed. Enzymes that are in the saliva start digesting starch as you are chewing.
When the food is swallowed, our tongue pushes a ball of food to the back of our mouth. The tube joining the mouth to the stomach is called the oesophagus or the gullet. The process is called peristalsis, where the muscles push balls of food along it.
The stomach stores food. It has elastic walls and can expand. It produces gastric juice, which is a mixture of hydrochloric acid and enzymes. The acid kills any germs and makes the conditions right for the enzymes to work. The stomach is coated with substances which stop the stomach from being digested by the acid or enzymes. The food now looks runny, warm and smelly, and is called chyme.
In the small intestine, digestions is completed. In the small intestine, it is covered with villi, which are semi-permeable and absorb soluble digested food which passes it into the blood vessels and lymph vessels inside them. The large intestine will thenabsorb water, vitamins and salts. The waste( Faeces ) will then be stored in the rectum, which will then be excreted from the anus.
Starch --> glucose--> maltose
Proteins --> Amino Acids
Fats --> Fatty acid + Glycerol
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