Table : Digestive System

SCIENCE Grade 7 DIGESTION

CHEMICAL DIGESTION ORGAN FUNCTION enzyme found in acts on breaks it down (liquid) into mouth – mechanical digestion: bite/cut (incisors) tear- canines teeth grind/crush pre-molars + molars food to reduce size of pieces + increase surface area chemical digestion: amylase saliva starch - sugars chew to mix with Saliva carbohydrate (glucose) oesophagus Peristalsis – pushes food down into stomach stomach mechanical digestion: 3 sets muscles contract- Peristalsis churn food into CHYME mixed with digestive juices + HCL chemical digestion + proteases gastric juices proteins polypeptides controls slow steady flow (pepsin) into stomach (pH 2 – acidic + conditions absorption - HCL made by cells in stomach lining)

AA 22nd April 2010 Page 1 of 2 SCIENCE Grade 7 DIGESTION gall bladder mechanical digestion: BILE stores bile  physically breaks up fat particles into small fat droplets  contains alkaline salts to neutralize any stomach acid which enters the small intestine and keep the pH in the intestines at 8 the liver produces BILE

stores glycogen + the pancreas produces enzymes for small Amylase starch intestine Trypsin protein Lipase fats small intestine chemical digestion proteases digestive protein amino acids (pH 8) juices amylase starch glucose + lipase lipids (fats + oils) fatty acids + absorption of: glycerol  nutrients the large intestine

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