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Human Digestive System 2.3 Prepared by: Wan Zhi Ling Lim Chia Yee Kong Chee Heng Cheah Ken Ji Teo Jing Tong

2.3 the human digestive system

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Text of 2.3 the human digestive system

  • 1. Prepared by:Wan Zhi LingLim Chia YeeKong Chee HengCheah Ken JiTeo Jing Tong

2. PARTS OF THE DIGESTIVE SYSTEM 3. 1.The digestive system consists of all theorgans which take part in the digestion offood.2.The alimentary canal consists of the partsthrough which food passes from the mouthto the anus. 4. THE MAIN FUNCTIONS OF THE ORGANS IN THE DIGESTIVE SYSTEMorgans functionMouth Keeps the food for chewingTeeth Cut the food into small piecesSalivary glands Produce saliva containing digestive enzyme (amylase)Tongue Taste the foodOesophagus Channels the food from the mouth into the stomachStomach Produces digestive enzymes (rennin and protease)Duodenum Digests the food with the help of enzymes from the pancreasPancreas Produces digestive enzymes(amylase, protease and lipase)Liver Produces bile for emulsifying fatsGall bladder Stores bile from the liverSmall intestine(ileum) Produces digestive enzymes and completesthe undiges foodLarge intestine Absorbs water from the undigested foodRectum Keeps the faecesAnus Lets out the faeces 5. THE PATHWAY OF DIGESTION OF FOODmouth oesophagus stomachduodenumSmallintestineLargeintestineanus 6. THE DIGESTION OF FOOD1. Digestion of food is the process of changing the food eaten fromlarge complex molecules into small simple molecules which canpass through the cell membrane into the cells of the body.The processof digestionPhysicalDigestiveChemicalDigestive 7. Physical DigestionWe broken the food into small piece.Chemical DigestionChanging the large complex food moleculesinto small simple molecules which can beabsorbed by the body. 8. In The Moutha)The food in the mouth is first cut intosmall pieces by the teeth and mixed withthe saliva.b)The enzyme in the saliva, amylase willchange the starch into maltose.c)Saliva is alkaline. 9. In The Oesophagusa)Peristalsis of the wall of theoesophagus pushes the food downthe oesophagus into stomach.b)No digestion of food is occurredhere 10. In The Stomacha)The food is mixed with the gastric juice producedby glands in the wall of the stomach.b)Gastric juice contains hydrochloric acid andenzymes(rennin and protease)c)The hydrochloric acid neutralises the alkali in thesaliva and prepares an acidic medium for the twoenzymes to act on the food. It also kills bacteria inthe food.d)Rennin coagulates milk so that it is more easilydigested.e)Protease digests proteins into peptones. 11. Peristaltic movement 12. In The Duodenuma)The duodenum is the first portion of the small intestine.b)In the duodenum, the food is mixed with the bile andpancreatic.c)Bile is a thick alkaline liquid produced by the liver andstored in the gall bladder. It neutralize the acid in thefood from the stomach and changes oil into droplets sothat it is easier for any enzymes to act on it.d)Pancreatic juice is very alkaline. It contains threeenzymes-amylase, protease and lipase.e)Amylase changes starch into maltose. Protease changesproteins into peptones. Lipase changes fats into fatty acidsand glycerol. 13. In The Small Intestinea)The second portion of the small intestineis called the ileumb)Digestion is completed in the ileum-carbohydrates are digested into simplesugars such as glucose and fructose.-Proteins and peptones are digestedinto amino acids 14. THEEND