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THE HUMAN DIGESTIVE SYSTEM The journey of food http://www.sciencefinder.co.uk OB6 identify and locate the major parts of the digestive system including the mouth, oesophagus, stomach,liver, pancreas, small intestine and large intestine, and know their functions http://www.sciencefinder.co.uk The Mouth. Teeth break down food into small pieces. Salivary glands make saliva. Chewed food gets mixed with saliva. Saliva contains enzymes, which start to digest starch to sugar. http://www.sciencefinder.co.uk The Oesophagus. Passes food down to your stomach. The oesophagus has circular muscles in its wall. These muscles contract and squeeze in behind the food to push it along. http://www.sciencefinder.co.uk The Stomach Muscular bag that holds 2 litres of food. Secretes hydrochloric acid. Makes digestive juices. Muscular walls churn the food making sure it’s all mixed. After 2-3 hours churning it’s a runny liquid. http://www.sciencefinder.co.uk The Small Intestine Actually 6 m long! Plays important roles in digestion and absorption Two important liquids are added here: Pancreatic juices Bile http://www.sciencefinder.co.uk Absorption Digested food has to pass into the blood through the gut wall. Well designed – thin lining, good blood supply and a VERY LARGE surface area. It has a folded inner lining, millions of tiny villi http://www.sciencefinder.co.uk Pancreas Produces digestive enzymes E.g. amylase http://www.sciencefinder.co.uk Liver After food has been absorbed into the blood, the food is taken to the liver. The liver processes some of it, before it goes any further. The food dissolved in plasma is the taken to other parts of the body. http://www.sciencefinder.co.uk The Large Intestine. Mainly fibre, dead cell, bacteria and water reach here! As it moves along here most of the water is absorbed into the blood. Faeces are stored in the rectum. Eventually egested out of the anus, roughly 24 –48 hours after eating. http://www.sciencefinder.co.uk http://www.sciencefinder.co.uk