b'Digestive SystemChapterThe digestive system provides the body with food and water. The two main functions are to process food and break it down into simple substances that can be absorbed into the blood supply to reach the body tissues and to remove body waste products.Digestion begins in the mouth, where chewing and saliva starts the process of breaking down food. Food and water is passed through the oesophagus intothe stomach where it is partly digested by gastric juices.Food with get to your stomach even if you are standingon your head. Most work is done by muscles pushingfood down (peristalsis).I t is then passed into the small intestine wherethe nutrients are absorbed into the blood.The liver and kidneys filter and remove unwantedsubstances. The gall bladder and pancreas also aid indigestion by processing food into chemical sub-stances (sugars, hormones, etc) used by the body.The material left over after digestion including dietary fibre, moves into the large intestine whereother nutrients, water and minerals are absorbed.The remainder is waste material that is eliminated through the rectum.Sitting together with the digestive organs in the abdomen is the spleenwhich is tucked up under the left ribs just below the diaphragm. The spleen is not actually a digestive organ and it is not vital for life.The main function of the spleen is to clear the circulation of old red blood cells and to produce new ones.This function can be taken over by the liver and bone marrow if the spleen is damaged or removed.Why is my liver red?Saliva The liver can completely regenerate itself if partly damaged. It is the only organ with You produce about 1.5this ability.litres of saliva every day! This is because it has an extremely largeIt keeps your mouthsupply of blood. moist, softens your foodAbout one quarter of all your blood flows and contains chemicalsthrough the liver.It stores vitamins and sugars, filters and called enzymes. These help breakdown food and startdestroys poisonous substances. t aids in digestion by producing a bitter the processIof digestion. green liquid (bile).Bile breaks down fat and is alsostored in the gall bladder.30 How Your Body Works'