Science Digestion

Teeth chew food into smaller pieces. Saliva lubricates the food to help in swallowing. Amylase in saliva starts to break down starches into glucose.

It takes about five seconds for food to pass through your oesophagus to your stomach. Smooth muscles squeeze in waves of contractions called peristalsis which moves the food around.

Food stays in your stomach for about 4 hour. Here it is mixed with hydrochloric acid that lowers the ph in the stomach and helps protease begin the digestion of proteins. It is now no longer called food it is chummed into a thick liquid called chyme.

Adds digestive enzymes in the small intestine.

Most of digestion takes place in the duodenum, the first part of the small intestine. A greenish fluid called bile is added. Which acts like a emulsifier to break down fats. By now, the chyme has been broken down into small molecules ready to be absorbed by the villi. The small intestine molecules of nutrients pass into the blood vessels of the villi.

Food passes into the large intestine. Excess water is absorbed into the large intestine.

Faeces is then eliminated through and opening called the anus.

A mixture of waste material, bacteria, and mucus are passed to the rectum where the mixture is compacted and readied for elimination. This could take up to two days.