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nutrition

nutrition. Food digestion. Substances needed in cell metabolism. Metabolism : chemical reaction in cells that keep them alive, growing & dividing Divided into: Catabolism – breaking down substances to produce energy & simpler molecules

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nutrition

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  1. nutrition Food digestion

  2. Tr.Rez@SB2013

  3. Substances needed in cell metabolism • Metabolism : chemical reaction in cells that keep them alive, growing & dividing • Divided into: • Catabolism – breaking down substances to produce energy & simpler molecules • Anabolism – using ATP to synthesize new cell components from simple molecules • Substances needed for metabolic processes: • Glucose • Amino acid • lipids Tr.Rez@SB2013

  4. Functions of glucose in cellular metabolism • Broken down to produce chemical energy (ATP) • ATP provide energy for all metabolic activities Tr.Rez@SB2013

  5. Functions of amino acid • basic building blocks of proteins • About 22 amino acids are used to synthesize the different type of protein required by the human body Tr.Rez@SB2013

  6. Lipids are used in the synthesis of: • Triglycerides (energy storage molecules) • Phospholipids (major building blocks of cell membrane) • Hormones and vitamins Tr.Rez@SB2013

  7. HUMAN DIGESTIVE SYSTEM Alimentary Canal

  8. Basic structure of alimentary canal • The walls of the alimentary tract are formed by 4 layers of tissue: • Adventitia / serosa – outer covering • Muscle layer • Submucosa • Mucosa - lining Tr.Rez@SB2013

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  11. Digestive juice

  12. Digestive juice • Saliva • Gastric juice • Pancreatic juice • Intestinal juice Tr.Rez@SB2013

  13. Saliva • Salivary amylase • pH 6.5 – 7.5 • Starch + water maltose Tr.Rez@SB2013

  14. Gastric juice • pH 1.5 – 2 • Hydrochloric acid • Lowers the stomach pH : pepsin activated • Pepsinogen pepsin • Pepsin • Protein + water polypeptides • Rennin • Caseinogen (milk protein) casein Tr.Rez@SB2013

  15. Pancreatic juice • pH 7.8 – 8.5 • Pancreatic amylase • Starch + water maltose • Trypsin • Protein / polypeptides + water peptides • Lipase • Fats + water fatty acid & glycerol Tr.Rez@SB2013

  16. Bile • Bile salts (not enzyme) • Fats fat droplets Tr.Rez@SB2013

  17. Intestinal juice • pH 7.6 • Erepsin • Peptides + water amino acids • Maltase • Maltose + water glucose • Sucrase • Sucrose + water glucose + fructose • Lactase • Lactose + water glucose + galactose • Lipase • Fats+ lipids fatty acids + glycerol Tr.Rez@SB2013

  18. Digestion of Carbohydrates, Protein & Lipids

  19. Digestion of Carbohydrates, Protein & Lipids • mouth • Oesophagus – no digestion takes place • Stomach • Small intestine – duodenum, jejunum & ileum • Large intestine – no digestion takes place • Rectum Tr.Rez@SB2013

  20. Mouth • Digestion of carbohydrates • Salivary glands – produce saliva • Saliva have 5 main components: • Water – moisten & soften food • Lysozyme – kill bacteria • Mucus • Sodium salts – provide alkaline medium Starch + water maltose amylase Tr.Rez@SB2013

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  22. Esophagus Tr.Rez@SB2013

  23. Stomach Tr.Rez@SB2013

  24. Gastric gland secrete gastric juice that contain: • Pepsin • Rennin • Mucus • HCl Tr.Rez@SB2013

  25. Pepsinogen + HCl pepsin • Prorennin + HCl rennin • pepsin • Protein + water polypeptides • Rennin • Caseinogen (milk protein) casein • Casein polypeptides Tr.Rez@SB2013

  26. Small intestine • Consist of • Duodenum • Jejunum • Ileum Tr.Rez@SB2013

  27. Digestion of protein • Trypsin • Protein + water polypeptides • Polypeptides + water peptides • Erepsin • Peptides + water amino acids • Polypeptides + water amino acids Tr.Rez@SB2013

  28. Digestion of lipids • Lipase • Lipids + water glycerol + fatty acids Tr.Rez@SB2013

  29. Digestion of carbohydrates • Amylase • Starch + water maltose • Maltase • Maltose + water glucose • Lactase • Lactose + water glucose + galactose • Sucrase • Sucrose + water glucose + fructose Tr.Rez@SB2013

  30. DIGESTION IN RUMINANTS & RODENTS

  31. Digestive system of a cow • Ruminant • Main structure: • Mouth • Oesophagus • Stomach • Small intestine • Large intestine Tr.Rez@SB2013

  32. Stomach • 4 compartments: • Rumen • largest • Reticulum • Contain symbiotic microorganism • Omasum • Abomasum • “true” stomach • Secretes pepsin & HCl Tr.Rez@SB2013

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  34. Digestive system of rat • Main structures & organs: • Oral cavity • Salivary glands • Pharynx • Oesophagus • Stomach • Small intestine • Caecum • Large intestine Tr.Rez@SB2013

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  37. ABSORPTION & ASSIMILATION

  38. Adaptations of the digestive system for absorption • Absorption of digested food: • Takes place in small intestine • Starts in the duodenum; completed in the ileum Tr.Rez@SB2013

  39. Adaptations of the small intestine to absorb digested food: • Large surface area • Long; covered with villi • Microvilli; one cell thick • Network of blood capillaries • Lacteal : fatty acids, glycerol & oil soluble vitamins Tr.Rez@SB2013

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  41. Absorption in small intestine • Blood capillaries absorb: • Amino acid • Monosaccharides • Vit B & C • Minerals • Water • Transport them to the liver via Hepatic portal vein • Liver filter & process absorb nutrients • Then send to hepatic vein and go to heart Tr.Rez@SB2013

  42. Lacteal absorb: • Fatty acids • Glycerol • Fat soluble vitamins (A,D,E,K) • Transport them from lymph vessels, to the thoracic duct Tr.Rez@SB2013

  43. Absorption in the colon • The colon: • Has no digestive activity • Has no vili • Epithelium lining is for absorption • Colon absorb: • Water • Vitamins (Folic acid, vitamin K & several vitamin B produced by bacteris Tr.Rez@SB2013

  44. Assimilation

  45. Assimilation • Products of digestion are brought directly to liver for processing, preparation for metabolic process • Takes place in the cells where the nutrients are used to form complex compound Tr.Rez@SB2013

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  47. Functions of the liver • Detoxifies poisonous substances • Maintain constant blood glucose level • Converts amino acids to glucose; if the body runs out glycogen to glucose • Maintains blood amino acid level • Regulate lipids • Removes hemoglobin molecules when RBC dies • Produces bile • Produces heat • Produces cholesterol Tr.Rez@SB2013

  48. FORMATION OF FAECES & DEFECATION

  49. The large intestine • About 1.5 m • Consist of 3 structures: • Caecum & appendix • Colon • Rectum • Main functions: • Absorb water & compact material into faeces • Absorb vitamins produced by bacteria • Stores faeces to be defecated Tr.Rez@SB2013

  50. Tr.Rez@SB2013

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