- The five stages of digestion are ingestion, digestion, absorpbtion, assimilation and egestion.
- Ingestion is the taking of food into the mouth.
- Digestion is the breaking down of food.
- Absorpbtion is the absorpbtion of molecules of food into the blood in the small intestine.
- Assimilation is the taking of food molecules from the blood into body cells.
- Egestion is the passing of undigested food out of the body.
- Physical digestion involves the chewing of food in the mouth and churning of food in the stomach.
- The four types of teeth are incisors, canines, premolars and molars.
- Chemical digestion is the breaking down of food by enzymes.
The Digestive System
- The digestive system is a group of organs working together to break down food and absorb the nutrients from it.
- The mouth chews food and mixes it with enzymes, eg amylase in syliva.
- The oesophagus carries food to the stomach by muscular action (peristalsis).
- The stomach stores and churns food and mixes it with digestive juices. It also produces hydrochloric acid to kill bacteria.
- The liver produces bile to break down fats.
- The small intestine contains enzymes to break down food. Food molecules are absorbed into the blood in the small intestine.
- The pancreas produces enzymes.
- The large intestine passes water into the blood.
- An enzyme is a chemical which speeds up a chemical reaction in the body without being used up in the reaction.
- An enzyme acts on a substrate to produce the product.
- Amylase is an enzyme which breaks down starch into maltose.