8A4 The digestive system Name the organs. Click to reveal the answers. stomach oesophagus large intestine small intestine rectum
What does the digestive system do? • Breaks up food into smaller pieces. • Breaks up proteins, carbohydrates and fats into smaller molecules. • Absorbs the smaller fragments and vitamins, minerals and water. • Gets rid of food that cannot be digested and other wastes.
The digestive system • The substances in foods must be digested before they can be used by the body. • Digestion happens in the mouth, the stomach and the small intestine. • Food is pushed along the gut by peristalsis. • Food is broken up by physical and chemical processes. • Small food molecules pass into the blood in the small intestine.
How does digestion work? Teeth and jaws crush food Saliva breaks down starch and coats food Food is pushed down oesophagus by peristalsis Stomach muscles churn food into a paste Gastric juices from the pancreas complete digestion in the small intestine Acid and gastric juices in the stomach break up proteins Faeces are stored in the rectum and pushed out of the anus Food materials are absorbed by villi in the small intestine Water is absorbed in the large intestine
The model gut • What do you predict will happen? • How will you detect starch or glucose? • The tubing is a model intestine, the starch and sugar is model food. What is the warm water round the tube a model of?
Key words Do you know what these sentences describe? Click to reveal the answers. Method of pushing food down the gullet peristalsis Finger-like extension in the small intestine villus Organ that makes gastric juices pancreas Wastes stored in rectum faeces
Name the parts Click to reveal the answers. salivary glands teeth stomach oesophagus large intestine small intestine anus rectum