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BIOLOGY FORM 4 CHAPTER 6 - NUTRITION PART 2

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BIOLOGY FORM 4 CHAPTER 6 - NUTRITION PART 2

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BIOLOGY FORM 4 CHAPTER 6 - NUTRITION PART 2

  1. 1. BIOLOGY FORM 4 CHAPTER 6 NUTRITION (6.4 – 6.8) PART 2
  2. 2. 6.4 FOOD DIGESTION
  3. 3. Objectives You will learn to: • Define and explain the importance of physical and chemical digestion. • Identify the main part of the human digestive system (mouth, salivary glands, oesophagus, stomach, small intestine, liver, gall bladder, pancreas, large intestine, rectum and anus). • Describe the functions of the mouth, salivary glands, oesophagus and stomach in relation to ingestion, movement of food along the gut, physical and chemical digestion. • Describe peristalsis in terms of rhythmic wave-like contractions of the circular and longitudinal muscles to mix and propel food along the alimentary canal.
  4. 4. Digestion is the process by which  insoluble food, consisting of large molecules is broken down into soluble compounds
  5. 5. What are starch, proteins & fats broken down into? enzyme enzyme enzyme STARCH PROTEIN FAT Glucose Amino acids Fatty acids & glycerol
  6. 6. Why must food be digested? Blood Blood Blood Food in intestine Food in intestine Food in intestine 1 3 2 Wall of intestine To be small enough to be absorbed through the wall of intestine. enzyme
  7. 7. Digestion starts at the mouth and ends at the ……………….anus
  8. 8. Food is broken down by two actions: 1. PHYSICAL /MECHANICAL 2. CHEMICAL
  9. 9. 1. PHYSICAL DIGESTION by:  teeth  peristalsis of the alimentary canal Chewing (mastication)
  10. 10. Why is it important to break down food physically? To increase the surface area for enzyme action.
  11. 11. Question: Give TWO reasons why food must be masticated before swallowed. (4) 1. Increased surface area for enzymes to act quickly. 2. Easier to manipulate by tongue to form a bolus.
  12. 12. 2. CHEMICAL DIGESTION by:  enzymes Digestive enzymes are the chemicals that break large insoluble food molecules into smaller soluble molecules.
  13. 13. Four stages in feeding & digestion: 1. Ingestion 2. Digestion 3. Absorption into the bloodstream 4. Egestion
  14. 14. Digested food is absorbed & then assimilated by the cells Digestive system Circulatory system Body cell Absorption Assimilation
  15. 15. Digestive tract is also called:  Alimentary canal / tract  Gut
  16. 16. Mucus is produced throughout the gut:  For lubrication  To protect gut wall from digestive enzymes
  17. 17. Fig. 1 The human digestive system.
  18. 18. The 1st stage of nutrition: 2. Digestion 1. Ingestion 3. Absorption 4. Egestion
  19. 19. DIGESTION IN THE MOUTH
  20. 20.  salivary glands produce SALIVA (pH = 7-8)
  21. 21. Salivation is a reflex action which is triggered by:  Sight  Smell  Thinking of food
  22. 22.  mucus  water  sodium hydrogen carbonate  salivary amylase (ptyalin [old term]) Saliva contains:
  23. 23. Functions of mucus in saliva: 1. lubricates the food 2. sticks the food particles together bolus
  24. 24. Salivary amylase
  25. 25. In swallowing, food is directed into the gullet / oesophagus
  26. 26. A person cannot breathe while swallowing. Why? 1. The soft palate closes the nasal cavity . 2. The epiglottis closes the trachea.
  27. 27. Swallowing
  28. 28. Peristalsis:  wave-like motions of the alimentary canal which move the food forwards 1 2 BolusDigestive tract Wave of contraction Wave of relaxation Bolus moves 2
  29. 29. Peristalsis: Note: Peristalsis occurs from the Oesophagus to the rectum!
  30. 30. Longitudinal muscle Circular muscle Part of the gut wall
  31. 31. Peristalsis is possible as gut wall is muscular  contraction of circular & longitudinal muscles alternate to push food
  32. 32. Food is pushed when: What does the longitudinal muscle do at the same time? Circular muscle above bolus CONTRACTS Relaxes
  33. 33. Circular muscle contract, Longitudinal muscle relax Wall of the gut constricts – It becomes narrower and longer Push the bolus forward Circular muscle relax, Longitudinal muscle contact Wall of the gut dilates – It becomes wider and shorter Lumen is widen for food to enter Mass of food Antagonistic action of the muscles
  34. 34. Food reaches the stomach
  35. 35. 1. Describe the functions of the stomach, duodenum, pancreas, gall bladder, liver, ileum, jejunum in relation to physical digestion, chemical digestion, absorption of nutrients and water. 2. State the function of proteases pepsin and rennin on proteins and list the end products of protein digestion in the stomach. 3. List the digestive enzymes produced by the intestinal glands and pancreas. 4. Describe the function of bile in the emulsification of fats. Objectives
  36. 36. The stomach stores food for some time & releases it slowly  Food stays for 2-6 hours in the stomach Chyme: creamy liquid leaving the stomach
  37. 37. Food remains inside stomach due to contraction of two sphincters Cardiac sphincter Oesophagus Duodenum Pyloric sphincter Layers of muscle Churning due to: Lining of mucus
  38. 38. Churning due to:
  39. 39. Which sphincter is contracted? Cardiac sphincter: Pyloric sphincter: contracted relaxes to let chyme into the duodenum
  40. 40. Gastric glands secrete gastric juice
  41. 41. What happens to food inside the stomach?
  42. 42. Gastric juice contains: 1. HYDROCHLORIC ACID 2. PEPSIN 3. RENNIN What is the pH in the stomach? 1-2
  43. 43. Functions of hydrochloric acid: 1. creates the optimum pH for pepsin Pepsinogen (inactive form) Pepsin (active enzyme) 3. kills bacteria taken in with the food 2. HCl
  44. 44. Excessive production of gastric juice: burning sensation
  45. 45. Gastric juice enters oesophagus: not enough mucus to protect wall
  46. 46. Remedy for burning sensation in throat and chest: 1. Drink milk 2. Take antacids
  47. 47. Doctors can see the stomach lining by using an: endoscope oesophagus
  48. 48. Stomach ulcers due to: little mucus in stomach
  49. 49. Stomach (2 enzymes secreted) Hydrochloric acid Pepsinogen Pepsin (active enzyme) Prorennin Rennin (active enzyme)
  50. 50. Why is pepsinogen produced instead of pepsin? To prevent pepsin from digesting the stomach walls
  51. 51. Pepsin is a protease:  breaks: Polypeptides Proteins
  52. 52. Which conditions are needed for a piece of meat to be digested?  Pepsin in acidic conditions
  53. 53. Question: The following diagram represents the protein found in egg white. Each circle represents an amino acid. Complete the diagram below to show how pepsin breaks down the protein found in egg white. [Idea is that short chains representing polypeptides are made.] (Do NOT accept individual amino acids represented as single circles or dipeptides represented as a pair of circles)
  54. 54. Question: List TWO reasons why amylase does not act on starch in the stomach. (2) i. pH in stomach is not optimum for amylase ii. there is no enzyme in the stomach to break starch
  55. 55. Some substances that are absorbed by the stomach:  ethanol  vitamins  certain salts and drugs  some water  glucose How did I get drunk so quickly?
  56. 56. Rennin  is an enzyme found in the stomach of young children  Function: Soluble protein in milk (caseinogen) Changes into insoluble protein (casein) Pepsin then acts on the insoluble protein
  57. 57. In cheese-making, rennet [contains rennin] is added to milk
  58. 58. Protein Digestion In Stomach Proteins Polypeptides Pepsin Soluble Insoluble milk proteins milk proteins (caseinogen) (casein) Rennin Casein Polypeptides Pepsin
  59. 59. Due to cancer of the stomach, the entire stomach of Patient A have being surgically removed. As the doctor of Patient A, you are to provide information on the effect on the lifestyle and digestive function upon removing the stomach.
  60. 60. • Stomach is the site of initial protein digestion. Removal of stomach will cause protein digestion to be greatly affected; • Patient A can rely only on the small intestine for protein digestion, rate of protein digestion will be lowered. • No HCl, prone to food infection by bacteria. • Need to reduce protein intake to avoid congesting the small intestine.
  61. 61. THE INTESTINES: Small intestine Large intestine 1.5 m long 7 m long
  62. 62. The small intestine is composed of: duodenum & jejenum & ileum
  63. 63. Two functions of the small intestine: 1. digestion is completed 2. digested food is absorbed Bloodstream Products of digestion
  64. 64. Duodenum  U-shaped  first part of small intestine (most digestion occurs here)  about 25 cm long
  65. 65. The duodenum receives secretions from the: Pancreas [pancreatic juice via the pancreatic duct] Liver [bile via the bile duct]
  66. 66. DIGESTION IN THE DUODENUM
  67. 67. Liver Pancreas Gall bladder Duodenum of Small intestine
  68. 68. Liver Pancreas Gall bladder Duodenum of Small intestine
  69. 69. Where is bile: i) made? ii)stored?
  70. 70. Made in liver Stored in gall bladder Transported through the bile duct
  71. 71. Bile:  has no enzymes  consists of:  water  sodium chloride  bile salts  bile pigments  pH = 8
  72. 72. Functions of Bile:  dilutes contents from stomach  creates optimum pH for pancreatic enzymes to work in duodenum  contains bile salts which emulsify fats Bile salts
  73. 73. Bile salts emulsify fats i.e.:  break large fat globules into smaller globules Emulsification of fats What is the benefit of emulsification? The surface area where lipase can act is increased.
  74. 74. Bile salts emulsify the fats by reducing the attractive forces between the fat molecules Physically breaks-up the fat molecules Bile Salts Tiny fat droplets Increase surface area to volume ratio – speed up digestion by lipase. Bile salts
  75. 75. A person had his gall bladder removed. Explain why the doctor told him to limit fats in the diet. Fats cannot be emulsified; difficult to digest fats by lipase.
  76. 76. Three enzymes in pancreatic juice: Pancreatic amylase Trypsin Pancreas Lipase Action of each enzyme:
  77. 77. lipase + fat molecule glycerol fatty acids starch molecule amylase maltose proteins & polypeptides trypsin peptides
  78. 78. Secrete Pancreatic Juice: • Pancreatic amylase, • Pancreatic lipase • Trypsinogen trypsin (active enzyme) Pancreas enterokinase
  79. 79. Question: Bile and pancreatic juice are involved in digestion of fats. a) Describe the role of both secretions in this process. (4) b) Explain why bile must be released before pancreatic juice for the efficient digestion of fats. (2)
  80. 80. DIGESTION IN THE ILEUM
  81. 81. The wall of the ileum has intestinal glands that produce intestinal juice
  82. 82. Secrete Intestinal juice Maltase Sucrase Lactase Erepsin Intestinal lipase Intestinal Gland
  83. 83. Enzymes in intestinal juice SUBSTRATE ENZYME END PRODUCT Peptides Erepsin Amino acids Lipids Lipase Fatty acids & glycerol Maltose Maltase Glucose + glucose Sucrose Sucrase Glucose + fructose Lactose Lactase Glucose + galactose
  84. 84. Remember: Pepsin Amino acids Peptides Polypeptides Proteins Trypsin Erepsin
  85. 85. Remember: Digestion of starch Starch Maltose Maltose (in ileum) Glucose Pancreatic Amylase Salivary Amylase (In Mouth) No digestion of starch in stomach (amylase is denatured) Maltase
  86. 86. Digestive Juice Remember:
  87. 87. Starch + water Summary 6.4 FOOD DIGESTION 1. Digestion in the MOUTH FOOD Mouth Salivary glands Salivary amylase bolus aesophagus maltose secrete chewing triggers rolled into enters (by peristalsis)# epiglottis
  88. 88. Digestion in Stomach Gastric glands Gastric juices HCl Acid Pepsin Rennin - pH 1.5 – 2.0 - Stops the activity of amylase - Kill bacteria In food Protein + water Polypeptides Caseinogen + water Casein
  89. 89. Digestion in duodenum Starch + water maltose Polypeptide + water peptides Lipid droplets + water glycerol + FA Pancreatic amylase trypsin lipase
  90. 90. Digestion in small intestine • Intestinal juice • Digestive enzymes : digestion of peptides & dissaccharides 1) Protein digestion • Peptides + water amino acids 2) Carbohydrates digestion ( Ma La S ) • Maltose + water glucose • Sucrose + water glucose + fructose • Lactose + water glucose + galactose erepsin maltase sucrase lactase
  91. 91. Region of Digestion Source Enzyme Action MOUTH Salivary glands Salivary amylase Starch Maltose STOMACH Gastric glands Pepsin Rennin Protein Polypeptide Soluble Insoluble milk proteins milk proteins SMALL INTESTINE Pancreas Intestinal glands Pancreatic Amylase Trypsinogen trypsin Pancreatic Lipase Maltase Erepsin Lipase Starch Maltose Protein Polypeptides Fats Fatty acids+ glycerol Maltose Glucose Polypeptides Amino acids Fats Fatty acids+ glycerol
  92. 92. Digestion is complete in the ileum. What happens to the digested food?
  93. 93. Objectives 1) Describe the structure of the inner wall of the small intestine and explain it’s role in terms of increased surface area for absorption of nutrients. 2) Explain the role of a lacteal and blood capillaries in the transport and absorption of nutrients. 3) Describe the functions of the colon, rectum and anus in relation to absorption of water and mineral salts, temporary storage and egestion of faeces.
  94. 94. Model of the ileum showing numerous villi Villus: a finger-like projection
  95. 95. Villi contain blood & lymph vessels Villi – plural of villus
  96. 96. Structure of a villus
  97. 97. A villus is adapted for absorption
  98. 98. The ileum is adapted to absorb digested food  by providing a LARGE surface area:  Folded walls  Has villi  Has microvilli
  99. 99. Inner wall of small intestine Why is there a need for numerous folds, villi and microvilli? To increase surface area for absorption of digested food substances – Increasing the absorption rate of water and digested food products
  100. 100. Ileum is adapted for absorption: 1. Ileum is long:  more time for digestion  a greater surface area for absorption 2. Villi:  increase surface area for absorption 3. Microvilli in epithelium:  increase surface area for absorption 4. Epithelium is very thin:  soluble products of digestion pass through quickly 5. Dense capillary network:  removes the digested food
  101. 101. Glycerol and fatty acids diffuse into the epithelium – form fat globules – enter the lacteals Lacteal transport fats away from the small intestine. Blood capillaries Lacteal Sugars, amino acids, are absorbed by diffusion into the blood capillaries Blood capillaries transport sugars and amino acids away from the small intestine. Epithelium Villi One cell thick Faster diffusion of the digested food products What is the epithelium one cell thick?
  102. 102. Would the absorption of nutrients be affected if digested food substances cannot be transported away by the blood capillaries? Explain your answer. Yes. To a certain extent
  103. 103. The continual transport of digested food substances maintains a concentration gradient for the absorption of digested food substances by diffusion Lower concentration of digested food substances in the lumen of the small intestine, glucose and amino acids are absorbed by active transport Mineral salts enter the blood capillaries by active transport
  104. 104. Absorption of digested food 1) Glucose & Amino acids - from lumen into the epithelial cells by facilitated diffusion - remaining nutrients – by active transport - from epithelial cells – absorbed into the bloodstream thru the blood capillaries in the villi - converge into the hepartic portal vein - Then transported to all parts of the body Lumen (glu & a.a) facilitated diffusion Epithelial cells bloodstream Hepartic portal vein blood capillaries all parts of the body
  105. 105. 2) Water Lumen epithelial cells blood capillaries 3) Water-soluble vitamins Epithelial cells blood capillaries 3) Fatty acids & glycerol Epithelial cells (tiny droplets) lacteals lympatic system Right lymphatic duct Thoracic duct Bloodstream Subclavian veins
  106. 106. Activity time! I need a doctor!
  107. 107. I need a doctor! You are a doctor that specializes on the ileum. As the doctor of a patient who is overweight and has the intentions to lose weight, what procedures can be done to help the patient lose weight? Explain your answer.
  108. 108. THE LARGE INTESTINE
  109. 109. The large intestine is composed of: 1.Caecum Anus 2. Appendix 4. Colon 3. Rectum
  110. 110. Material in the large intestine consists of:  water  mucus  dead cells  undigested matter Most of the undigested matter is cellulose. Why is this so?
  111. 111. Function of the: Colon: absorbs 90 % water & mineral salts Rectum: stores FAECES before being expelled through the ANUS
  112. 112. 6.6 FORMATION OF FAECES & DEFAECATION
  113. 113. The 4th stage of feeding & digestion: 4. Egesting
  114. 114. Contents of Faeces: 1) undigested food 2) dead cells shed from the intestinal lining & bile pigments & toxic subtances – eliminated from the body 3) binds to the mucus that secreted by the colon’s wall and lubricates the movement of faeces along the colon
  115. 115. Defaecation • How it works?? - elimination of faeces - controlled by muscles around the anus, the opening of the rectum - When rectum is full, the muscles of the rectal wall contract to eject the faeces via the anus
  116. 116. Egestion / Defaecation  the process of removing faeces I really have to go to the bathroom!
  117. 117. Ingestion (2 L) Salivary gland secretions (1 L) Gastric secretions (2 L) Pancreatic secretions (1.2 L) 1% in faeces Small intestine secretions (2 L) Bile (0.7 L) Although 8.9 L of water are ingested or secreted daily, the faeces are dry. Explain.
  118. 118. Ingestion (2 L) Salivary gland secretions (1 L) Gastric secretions (2 L) Pancreatic secretions (1.2 L) Absorbed in the small intestine & colon. 1% in faeces Small intestine secretions (2 L) Bile (0.7 L)
  119. 119. Problems related to food digestion Incomplete digestion Lack of digestive enzymes Gallstones
  120. 120. Causes: • when people eat too much or too fast, or certain foods don't agree with them. • smoke, drink alcohol, are stressed out, or don't get enough sleep. • certain stomach problems, like gastritis (stomach inflammation) or an ulcer. Indigestion or dyspepsia or upset stomach. symptoms: pain or burning in your upper belly nausea bloating uncontrollable burping heartburn Prevention: Avoid fatty, greasy foods, like fries , burgers. Avoid too much chocolate or citrus fruits Eat slowly. Don't smoke. relax. Give your body a chance to digest food.
  121. 121. Gallstones Gallstones are hard deposits in your gallbladder Gallstones may consist of cholesterol, salt, or bilirubin, which are discarded red blood cells. Causes: • Too much cholesterol • Too much bilirubin • Gallbladder doesn’t empty properly Treatment: • Surgery • Medication • Home remedy :
  122. 122. 6.5 THE PROCESSES OF ABSORPTION & ASSIMILATION
  123. 123. OBJECTIVES You will learn: • 1) Define assimilation as the process where the products of digestion are distributed and use as an energy source or converted into protoplasm required for growth and repair of worn-out parts. • 2) State the role of the hepatic portal vein in transporting sugars and amino acids to the liver. • 3) Explain how sugars, amino acids and fats are utilised in the body. • 4) State that the hormone insulin is produced by islets of Langerhans in the pancreas. • 5) Explain the effect of insulin on glucose.
  124. 124. Assimilation The distribution and use of the digested food products as an energy source or converted into protoplasm required for growth and repair of worn-out parts - Assimilation Small intestine
  125. 125. ASSIMILATION • Definition - the conversion of nutrient into the fluid or solid substance of the body, by the processes of digestion and absorption - occurs in the LIVER and the CELLS
  126. 126. BLOOD SUPPLY OF THE LIVER
  127. 127. Oxygenated blood from heart Blood from digestive system HEPATIC PORTAL VEIN HEPATIC ARTERY LIVER HEART HEPATIC VEIN to heart INTESTINES Blood supply to and away from the liver
  128. 128. Transport of food substances Hepatic Portal vein Small intestine Liver Blood capillaries Gall bladder Bile Duct Absorbed food substances (sugars and amino acids) are transported via the hepatic portal vein to the liver Note: Fats are transported through the lacteal into the lymphatic system
  129. 129. Assimilation in the LIVER 7 Functions of the LIVER 1) Regulation of blood glucose concentration 2) Production of bile 3) Protein synthesis 4) Iron storage 5) Deamination of amino acids 6) Detoxification 7) Heat production
  130. 130. Assimilation in the LIVER synthesisconverts glucose excess DEAMINATION urea kidney - excess glucose - enter heart through subclavian veins
  131. 131. Transport and utilization of Glucose Small intestine Function of glucose: Glucose is used by all cells as a source of energy. Hepatic vein Some glucose is transported by the blood leaving the liver to other parts of the body Excess glucose is converted to glycogen and stored in the liver. Hepatic portal vein Glycogen
  132. 132. Conversion of Glucose Islets of Langerhan cells in the pancreas – secretes a hormone Insulin Insulin stimulate the liver to convert excess glucose to glycogen and stored.
  133. 133. Transport and utilization of Amino acids Amino acids pass through the liver before they are transported to the rest of the body. Small intestine Hepatic vein Function of amino acids: • Make new cells for growth • Replace worn-out cells • Make useful substances such as enzymes and hormones Excess amino acids are deaminated. Hepatic Portal Vein
  134. 134. Deamination occurs in the liver AMMONIA AMINO ACID is broken into two: The rest is used for energy Part with nitrogen forms: UREA
  135. 135. Question: Write the correct term for each of the following processes: i) the breakdown of excess amino acids Deamination ii) rhythmical muscular contractions that push food along the digestive system Peristalsis
  136. 136. iii) the elimination of indigestible food from the body Egestion / Defaecation iv) the passage of digested food through the gut wall in the blood stream. Absorption
  137. 137. Transport and utilization of Fats Fats is transported from the Lacteal  Lymphatic vessels  Bloodstream  Rest of the body and Liver Lacteal
  138. 138. Transport and utilization of Fats Fate of Fats • Use to form parts of the cell such as cell membrane • Prevent excessive heat loss. Excess fats stored in adipose tissues When glucose supply is low, fats are broken down in the liver to provide energy
  139. 139. ASSIMILATION OF DIGESTED FOOD FOOD USE STORE Glucose Respiration Glycogen or Fat Fats Respiration, to build cell structure, as a store of energy Fat Amino acids Build proteins for cell structures, enzymes CANNOT BE STORED – ARE DEAMINATED & USED IN RESPIRATION
  140. 140. Write an account of a controlled experiment you would perform to show the action of the enzyme amylase on starch. (6) Two spotting tiles are prepared with a drop of iodine solution in each hole. An equal volume of starch is placed into two separate test tubes, labelled A and B. 1 2
  141. 141. An equal volume of amylase is placed into two separate test tubes, labelled C and D. Test tube C is boiled for 5 minutes to denature the enzyme and so act as a control. All four test tubes are placed in a water bath at 37C for 5 minutes to acclimatise. 3 4
  142. 142. Starch in test tube A is poured into amylase in test tube D, mixed and the stop watch is started. 5 After 30 seconds, a drop of the mixture is taken and added to one of the drops of iodine solution on the spotting tile. This is repeated until a yellow colour appears. 6
  143. 143. Starch in test tube B is poured into amylase in test tube C, mixed and the same method is repeated. 7 8 Contents in test tube: i) D give a yellow colour with iodine solution after a few minutes ii) C continues to give a blue- black colour after 30 minutes.
  144. 144. 9 The results show that amylase breaks down starch. 10 If Benedict’s solution is added to the contents of test tubes C and D and heated for a few minutes, a brick red colour is obtained only in test tube D [unboiled amylase]. This shows that when starch breaks down, reducing sugars are formed. C D
  145. 145. What processes take place in the same part of the alimentary canal where ingestion of food takes place? 1. Physical digestion only 2. Chemical digestion only 3. Physical and chemical digestion 4. Digestion and absorption
  146. 146. Which of the following statement(s) about the Oesophagus is/are true? I. There is no digestion occuring in the oesophagus II. Food moves down the oesophagus via peristalsis III. There is digestion of starch in the oesophagus IV. The wall of the oesophagus secrete digestive enzymes 1. II and III only 2. I and II only 3. II and IV only 4. II only
  147. 147. Complete the following equations Starch _____________ Protein ______________ Fats _______________ amylase proteases lipase Maltose Amino acids Fatty acids + glycerol
  148. 148. Why are bile salts not considered enzymes? Bile salts does not digest fats, it only emulsify fats – Increase surface area for digestion by lipase.
  149. 149. TRUE / FALSE Fat digestion will stop if the bile duct is blocked by gallstones. False . Fat digestion will not stop But will become very slow since bile is absent to emulsify fats
  150. 150. At which part of the digestive system is digestion of all food completed. 1. Stomach 2. Colon 3. Oesophagus 4. Ileum
  151. 151. Which of the following listed below is not a feature of the ileum? 1. The inner surface is folded. 2. It releases gastric juice. 3. It is a very long tube. 4. Its main function is the absorption of digested food.
  152. 152. The diagram below shows part of the human digestive system and the associated blood vessels. Blood vessel X would least likely contain _____________ 1. Glycerol 2. Amino acids 3. Water 4. Glucose X
  153. 153. The diagram below shows the percentage of proteins, carbohydrates and fats digested as they pass through the alimentary canal in man. Which is PART C likely to be? 1. Ileum 2. Duodenum 3. Stomach 4. Oesophagus Percentageofundigested foodmolecules
  154. 154. How would the composition of the blood in the hepatic vein change if there was a high intake of protein-rich food? Explain. The composition of the blood would not change since excess amino acids caused by the high intake of protein-rich food will be deaminated in the liver.
  155. 155. 6.4 FOOD DIGESTION (continuation)
  156. 156. DIGESTION IN RUMINANTS & RODENTS
  157. 157. RUMINANTS
  158. 158. Digestive System of Ruminants
  159. 159. 1.Rumen 2. Reticulum 4. Abomasum 3. Omasum STOMACH – 4 Chambers
  160. 160. Digestive System of Ruminants
  161. 161. How it works?? 1.RUMEN - Largest compartment - Cellulose broken down by cellulase (bacteria & protozoa) 2.RETICULUM - Further hydrolysis - CUD – its content - Regurgitated bit by bit - Soften & break down cellulose mouth3.OMASUM -Reswallowed cud -Large  small particles by peristalsis -Water is removed 4. ABOMASUM -True stomach - gastric juices secreted – protein digested Small intestine Lembu Makan R – Rumput R – Redah O – Onak dan A – Air Busuk
  162. 162. Rodents Cellulose digested by cellulase-producing bacteria in caecum
  163. 163. Rodents
  164. 164. Rodent Digestion -Faeces 1st batch - soft & watery -2nd batch faeces – drier & harder • Caecum & appendix = enlarged to store cellulase-producing bacteria • products pass through alimentary canal = TWICE
  165. 165. Rodent Digestion
  166. 166. Comparison of cellulose digestion process in human, ruminant & rodent Similarities 1) 2) Differences Aspect Human Ruminant Rodent Stomach chambers Cellulase producing bacteria Food passes through alimentary canal Gastric juice is produced in Size of caecum Undigested cellulose
  167. 167. Caecum & Appendix are  Large in herbivores Vestigial in humans: [small & no function] Caecum Appendix
  168. 168. Question: Humans are omnivores. Do not depend only upon vegetation for nutrients. A large caecum is found in herbivores and is full of bacteria that produce cellulase to digest cellulose. Explain why the caecum / appendix in humans is small and non-functional. (4) Human Rabbit
  169. 169. THE END
  170. 170. Animal Nutrition Oral Cavity Carbohydrate Digestion Physical Digestion Salivary Amylase Starch Maltose Teeth Tongue Food Smaller Pieces Mix Food Bolus Oesophagus Peristalsis Antagonistic Muscles Circular Longitudinal Stomach Protein Digestion Gastric Juice Enzymes HCl Acidic MediumPepsin Rennin Protein Polypeptides Soluble Milk Proteins Insoluble Caesin Small Intestine Carbohydrate Digestion Protein Digestion Fat Digestion Pancreatic Amylase Intestinal Maltase Pancreatic Trypsin Intestinal Peptidase BilePancreatic Lipase Intestinal Lipase Fats Smaller Globules Polypeptides Amino acids Starch Maltose Fatty Acids Glycerol Liver Large Intestine Colon Rectum Faeces Anus DetoxificationDeamination Glycogen storage involves involved in by hydrolyses into involves break down into into helps involved in involves that are involved in by contains provides for consist of hydrolyses into into coagulates hydrolyses hydrolyse hydrolyse into into into involved in Consists of involves involves involves emulsifies into is involved in is for storing is egested via Eventually lead to has functions like Blood glucose level Breakdown of fatty acids to regulate EnergyAmino Acids to provide Breakdown of haemoglobin Recycle iron of Heat production Body temperature to regulate hydrolyses Maltose Monosaccharides Transported by into Blood capillaries Transported by Lacteals to Absorption of H2O and Mineral salts
  171. 171. 6.7 EVALUATING GOOD EATING HABITS
  172. 172. Problems related to food digestion Gastritis Obesity Anorexia nervosa Bulimia
  173. 173. What is gastritis?
  174. 174. What is gastritis? ( Gastritis is basically the condition where the mucosa (which is the stomach lining) becomes inflamed.
  175. 175. • Causes: • excessive alcohol consumption • prolonged use of nonsteroidal anti-inflammatory drugs. • Sometimes after major surgery, traumatic injury or burns
  176. 176. OBESITY
  177. 177. What happens to a person’s weight when: Weight remains constant
  178. 178. What happens to a person’s weight when: Weight increases Obese person
  179. 179. What happens to a person’s weight when: Weight decreases
  180. 180. • We can say that obesity is an increase in bodyweight (>20% over BMI) because of excess body fat. What is obesity?
  181. 181. What is obesity? • Obesity is a disease! Obesity is a chronic disease caused by excess weight.
  182. 182. • Affects men and women of all ages • Predominates in developed countries. What is obesity?
  183. 183. • The World Health Organization considered this disease as an epidemic of the 21st century. What is obesity?
  184. 184. Causes Sedentary life  Don’t do physical exercise;  See a lot of television;…
  185. 185. Extreme consumption Incorrect alimentary habits  Eat fast food; poor foods… Causes
  186. 186. Causes Genetic cause (rare)
  187. 187. Consequences Arteries disease Cancer Obesity Problems in the biliary vesicle Renal disease Alterations in the bones Heart disease & Hypertension Diabetes Lung diseases
  188. 188. Consequences Arteries disease Cancer Obesity Problems in the biliary vesicle Renal disease Alterations in the bones Heart disease & Hypertension Diabetes Lung diseases It can cause death !
  189. 189. Consequences And… • Social isolation; • Depression and loss of auto-esteem.
  190. 190. Consequences And… • Social and educative discrimination;
  191. 191. What to do to avoid? • Eat healthy food;
  192. 192.  Physical exercice; What to do to avoid?
  193. 193. • Medical help when obesity starts to be serious. What to do to avoid?
  194. 194. Look in the mirror. What do you see? Is it the real you or just another "me"?
  195. 195. What is an Eating Disorder? • mental illnesses • cause serious disturbances in a person’s everyday diet. • eating extremely small amounts of food or severely overeating.
  196. 196. Anorexia nervosa
  197. 197. • Individuals have a distorted body image that causes them to perceive themselves as overweight even when they are emaciated • They often lose large amounts of weight because they refuse to eat, exercise compulsively, or refuse to eat in front of others • Females experience loss of menstrual cycles • Males become impotent (erectile dysfunction)
  198. 198. Anorexia Nervosa: Warning Signs  Dramatic weight loss  Refusal to eat certain foods or food categories.  Consistent excuses to avoid situations involving food  Excessive and rigid exercise routine  Withdrawal from usual friends/relatives
  199. 199. Health Risks with Anorexia Heart failure Kidney failure Low protein stores Digestive problems Menstrual cycle stops
  200. 200. Bulimia Nervosa An eating disorder in which one starts to consume large amounts of food at once and then is followed by purging, using laxatives, or overexercising to rid themselves of the food they ate.
  201. 201. Bulimia Nervosa: Warning Signs  Wrappers/containers indicating consumption of large amounts of food  Frequent trips to bathroom after meals  Signs of vomiting e.g. staining of teeth, calluses on hands  Excessive and rigid exercise routine  Withdrawal from usual friends/relatives
  202. 202. Health Risks with Bulimia • Dental problems • Stomach rupture • Menstruation irregularities
  203. 203. deaths were caused by eating disorders in the U.S. in eating disorder deaths. In 2009 The U.S. is ranked
  204. 204. • Low Self-esteem • Feelings of inadequacy or failure • Feelings of being out of control • Response to change (puberty) • Response to stress (sports or dance) • Personal illness
  205. 205. • Troubled family and personal relationships • Difficult expressing emotions and feelings • History of being teased or ridiculed based on size or weight • History of physical or sexual abuse
  206. 206. • Cultural pressures that glorify thinness and place value on obtaining the perfect body • Narrow definitions of beauty that include women and men of specific body weights and shapes • Cultural norms that value people on the basis of physical appearance and not on inner qualities and strengths
  207. 207. • Seven feet tall • 38 inch chest • 21 inch waist • 36 inch hips • Virtually unattainable for an adult woman
  208. 208. http://www.youtube.com/watch?v=J_ax0h9F Nag&feature=endscreen
  209. 209. WHAT IS THE THREATMENT FOR AN AND BN?
  210. 210. • Psychotherapy • Support or self-help groups • Medical treatment • Nutritional treatment • Medication • Hospitalization
  211. 211. 6.8 IMPORTANCE OF A HEALTHY DIGESTIVE SYSTEM
  212. 212. TO PREVENT DISEASES OF THE STOMACH • Gastritis, Gastric Ulcer, Stomach Cancer, Hemorrhage from the Stomach, Hyperacidity, Dyspepsia OTHER DIGESTIVE DISEASES • Hepatitis, Diarrhea, Cirrhosis, Lactose Intolerance, Short Bowel Syndrome, Appendicitis, Constipation, Gallstones, Flatulence and Abdominal Adhesions
  213. 213. nuts, beans, grain, wheat, rice, vegetables and fruits 1. Eat foods rich in fiber  it helps the body eliminate waste, lowers cholesterol, feeds healthy bacteria and reduces risks of irritable bowel syndrome and colon cancer
  214. 214. 2. Eat good amounts of fish  Fish contain omega-3 fatty acids which can improve certain digestive problems because of their special anti-inflammatory properties.
  215. 215. 3. AVOID PROCESSED FOODS!  processed foods may contain ingredients which irritate the stomach
  216. 216. Avoid Junk food - empty calories, minimum nutrients - Artificial colourings, flavourings
  217. 217. Avoid food with high sugar /fat content - Prevent diabetes, obesity, cardiovascular disease
  218. 218. 4. Take Good Bacteria – THE GOOD BACTERIA
  219. 219. FOOD RICH IN PROBIOTICS Probiotics are good bacteria that live in the gastrointestinal system. They maintain its health by keeping bad bacteria at bay and creating a good harmony in your digestion's ecosystem. They have been known to help ease conditions like gastroenteritis, irritable bowel syndrome and inflammatory bowel disease.
  220. 220. DO DON’T 5. Develop good eating habits
  221. 221. 6. Exercise regularly  Exercise is great for boosting your body's natural functions and can improve the natural rhythm of your digestive system, too. It is also great for helping your food move through the digestive tract.
  222. 222. DO DON’T 7. Choose healthy hydration
  223. 223. THE END

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