1. Unit 2: The continuation of life Chapter 22: Delivery of Materials to cells (NUTRIENTS) 30/11/2015Mrs Smith Ch22 The delivery of nutrients to cells 1 Higher Human Biology

2. 30/11/2015Mrs Smith Ch22 The delivery of nutrients to cells 2 Learning Intentions To understand how nutrients are delivered by the bloodstream to every living cell in the body.. Success Criteria 1.Explain how glucose and amino acids, the end products of digestion of carbohydrates and proteins, are absorbed into the blood stream. 2.Identify the parts of a villus and explain how it is adapted to its function. 3.Describe the role of the lacteal in transport of absorbed lipid.

3. Preparation for nutrient absorption Food is moved along the alimentary canal from the mouth, to the small intestine by peristalsis. View the Peristalsis animation: http://www.westga.edu/~lkral/peristalsis/ As this happens digestive enzymes breakdown….. large insoluble food molecules small soluble molecules 30/11/20153Mrs Smith Ch22 The delivery of nutrients to cells

4. mouth anus stomach Large intestine Gall bladder Salivary glands Small intestine Oesophagus Rectum Pancreas liver appendix SG Revision: Labelling exercise 30/11/20154Mrs Smith Ch22 The delivery of nutrients to cells

5. Enzymes: Scholar Activity 30/11/2015Mrs Smith Ch22 The delivery of nutrients to cells 5 http://courses.scholar.hw.ac.uk/vle/scholar/session.controller? action=viewContent&contentGUID=e6928e85-bb13-a0f0- 102d-f1072a4fcd30

6. Answers Scholar Activity 30/11/2015Mrs Smith Ch22 The delivery of nutrients to cells 6 http://courses.scholar.hw.ac.uk/vle/scholar/session.controller? action=viewContent&contentGUID=e6928e85-bb13-a0f0- 102d-f1072a4fcd30

7. Digestive Enzymes: revision Digestive enzymes at various parts of the digestive system act on different types of food molecule… Small Intestine 30/11/20157Mrs Smith Ch22 The delivery of nutrients to cells

8. 1. Small Intestine 30/11/20158Mrs Smith Ch22 The delivery of nutrients to cells

9. 1. Small Intestine The small intestine is well suited to food absorption because: 3. Each villus has a lacteal & blood capillary network for efficient transport of absorbed substances 1. It is long 2. It has a folded inner lining covered in villi …So has a large surface area for absorption 4. The lining of each villi is one cell thick – so nutrients can pass through easily 30/11/2015 9

10. Epithelial cells, bearing microvilli, project into the lumen of the gut Intestinal gland between the villi; contains enzyme secreting cells and hormone releasing cells 30/11/201510Mrs Smith Ch22 The delivery of nutrients to cells

11. Glucose and amino acids, the soluble end products of carbohydrate and protein digestion, are absorbed into the epithelial cells from where the pass directly into the blood capillaries. The products of lipid digestion also pass to epithelial cells but instead of blood capillaries enter the central lacteal. 30/11/2015Mrs Smith Ch22 The delivery of nutrients to cells 11 2. Absorption of nutrients

12. Nutrients requiring no digestion by enzymes are also absorbed by the lining of the small intestine. These include calcium, iron and many vitamins. Remember Vit B12 can only be absorbed if intrinsic factor (a poly peptide made by the stomach) is present to stimulate endocytosis by the membrane of the epithelial cells. 30/11/2015Mrs Smith Ch22 The delivery of nutrients to cells 12 2. Absorption of nutrients

13. Glucose amino acids fatty acids and glycerol phosphates BLOODBLOOD Carbohydrates Proteins Lipids large insoluble food molecules small soluble molecules Absorbed into blood Absorbed into lacteal digestion Nutrients that don’t need to be digested (e.g. calcium, iron & vitamins) by enzymes are also absorbed by the small intestine. 30/11/201513Mrs Smith Ch22 The delivery of nutrients to cells

14. 30/11/2015Mrs Smith Ch22 The delivery of nutrients to cells 14 Learning Intentions To understand how nutrients are delivered by the bloodstream to every living cell in the body. Success Criteria 4.Carry out an experiment to examine the effects of bile salts i) as an emulsifier and ii) on the activity of lipase

15. Bile salts Bile salts are…. Stored in the gall bladder. Pass into the small intestine via the bile duct Produced in the liver 30/11/201515Mrs Smith Ch22 The delivery of nutrients to cells

16. Bile salts help us break down fat Bile is necessary for efficient digestion of lipids. During a meal, bile is secreted from the gallbladder into the small intestine. In the small intestine, bile helps to break dietary fat into smaller particles, a process called emulsification. Emulsified fat can be more easily acted upon by digestive enzymes. Without bile, digestion and absorption of fat is incomplete. 30/11/2015Mrs Smith Ch22 The delivery of nutrients to cells 16

17. Investigating the effect of bile salts as an emulsifier Lipids are, insoluble in water and less dense than water (so float). ABABAB Olive oil Water Bile salts solution Emulsification – oil droplets in water Olive oil Water Bile salts act as an emulsifier so oil still emulsified Shaken Emulsifier = a substance that preserves emulsion. 30/11/2015 17 Mrs Smith Ch22 The delivery of nutrients to cells

18. Discussion In test tube A, when the layers are shaken vigorously, the become mixed forming an EMUSION of tiny oil droplets. This does not last long the oil droplets settle to the top into two distinct layers again. 30/11/2015Mrs Smith Ch22 The delivery of nutrients to cells 18 In test tube B, when the layers are shaken vigorously, they again form EMUSION. However in this case the emuslsuin does not separate into two separate layers.

19. Conclusion An EMULSIFYER is an agent which reserves an emulsion. From this experiment it can be concluded that bile salts act as an emulsifier. 30/11/2015Mrs Smith Ch22 The delivery of nutrients to cells 19

20. Action of Bile Salts Bile salt molecule: Tail lipid soluble hyrdophobic (water-hating) Head water soluble hyrdophilic (water-loving) When shaken, with a lipid, the bile salt molecule becomes attached to the lipid with the lipid soluble tails pointing in to the centre. Droplet of lipid Bile salt molecule acting as an emulsifier The heads are negatively charged so the lipid droplets repel each other and don’t rejoin. This is emulsification. 30/11/201520Mrs Smith Ch22 The delivery of nutrients to cells

21. FYI: What are Gallstones Gallstones form when bile hardens into a small pebble-like substance that can grow as big as a golf ball due to high cholesterol, too much bilirubin, or inadequate bile salts. 30/11/2015 Mrs Smith Ch22 The delivery of nutrients to cells 21 In the event, when gallstones clog these ducts, it causes inflammation to the gallbladder wherein if it stays there for a longer period of time, it can result to a severe damage or infection to the gallbladdder, liver or pancreas.

22. Lipase  A digestive enzyme made in the pancreas  Active in the small intestine where it catalyses the breakdown of lipid molecules by cleaving off the first and third fatty acid molecules. 30/11/201522Mrs Smith Ch22 The delivery of nutrients to cells

23. Lipase SUBSTRATE END PRODUCTS Lipid molecule (triglyceride) + monoglyceride Free fatty acids LIPASE 30/11/201523Mrs Smith Ch22 The delivery of nutrients to cells

24. Investigating the effect of bile salts on the action of lipase ABC ABC Shaken + alkali added to make pH 7 then left for 30 mins in water bath at 37˚C Olive oil Lipase Water Bile salts Universal indicator pH 4pH 5pH 7 Acid conditions due to breakdown of lipids to fatty acids by lipase No digestion from bile salts alone Lower pH shows bile salts aid digestion of lipid to fatty acid 30/11/201524Mrs Smith Ch22 The delivery of nutrients to cells

25. Investigating the effect of bile salts on the action of lipase Here the lipid substrate is being used in olive oil. After 30 minutes the contents of tubes A and B are found to show a drop in pH indicating the presence of acidic conditions. It is therefore concluded that lipase has promoted the breakdown of lipid to fatty acids in tubes A and B. 30/11/2015Mrs Smith Ch22 The delivery of nutrients to cells 25

26. Significance of the control tube Since no change in pH is found to occur in tube C, it is concluded that lipase is required to catalase the digestion of lipid and that bile salts alone are unable to bring about the digestive reaction 30/11/2015Mrs Smith Ch22 The delivery of nutrients to cells 26 Comparing tube A and B A has undergone a greater drop in pH than B. It is therefore concluded that more digestion of lipid to fatty acids occurs when bile salts are present.

27. Bile salt molecules maintain an emulsion of lipid droplets. This increases the relative surface area of the lipid exposed to the lipase enzyme, so increases the number of substrate molecules that the enzyme can act on, thus aiding digestion. Droplet of lipid Bile salt molecule acting as an emulsifier Why do bile salts aid digestion by lipase? 30/11/201527Mrs Smith Ch22 The delivery of nutrients to cells

28. Following digestion, monoglycerides and fatty acids, the end products of lipid digestion, combine with bile salts to form tiny water-soluble particles called micelles. Micelles move to the surface of the intestinal epithelium, which has microvilli. Absorption of the end products of lipid digestion Fatty acids and monoglyceride molecules leave the micelles and diffuse through the cell membrane into the epithelium. 30/11/201528

29. Video: Micelles 30/11/2015Mrs Smith Ch22 The delivery of nutrients to cells 29

30. Absorption of the end products of digestion They are then coated with lipoprotein and move out of the cell by exocytosis. Lipid molecule (triglyceride) fatty acids monoglyceride + After passing through the epithelium of the microvilli, the monoglycerides & fatty acids pass into the cell’s endoplasmic reticulum to be built back into lipid molecules (triglycerides). E.R. Lipoprotein coat Exocytosis Absorbed by lacteal They get absorbed by the lacteal and are transported via the lymphatic system to the blood. 30/11/2015 30Mrs Smith Ch22 The delivery of nutrients to cells

31. Task: Torrance-TYK pg169 Qu 1-3 30/11/201531Mrs Smith Ch22 The delivery of nutrients to cells

32. 30/11/2015Mrs Smith Ch22 The delivery of nutrients to cells 32 Learning Intentions To understand how nutrients are delivered by the bloodstream to every living cell in the body. Success Criteria 5.Explain why the liver needs a dual blood supply 6.Analyse data on the composition of plasma of hepatic artery, hepatic vein and hepatic portal vein.

33. 4. The Liver Hepatic artery carries oxygenated blood to liver Hepatic vein carries deoxygenated blood from the liver to the vena cava Hepatic portal vein carries deoxygenated blood to the liver directly from the gut 30/11/201533Mrs Smith Ch22 The delivery of nutrients to cells

34. Portal System The portal system is circulation where blood in a capillary bed (e.g. gut) passes through a vein (e.g. hepatic portal vein) and into a second capillary bed (e.g. liver) before returning the normal circulation system. This prevents the end products of digestion entering directly into the circulation system. They are passed through the liver instead, which removes anything toxic by metabolism or excretion and converts nutrients into useable or stored forms. 30/11/201534Mrs Smith Ch22 The delivery of nutrients to cells

35. Composition of plasma In liver: excess glucose stored as glycogen excess amino acid converted to urea Hepatic artery contains blood with all essential nutrients + normal urea concentration Hepatic portal vein contains blood plasma with high concentrations of the end products of digestion + normal urea concentration Hepatic vein contains normal blood plasma concentrations of glucose & amino acids + high urea concentration Try the scholar activity: http://courses.scholar.hw. ac.uk/vle/scholar/session. controller?action=viewCo ntent&contentGUID=8f3 0977c-4cb9-fe59-4dfa- 86bf98b62bdd 30/11/2015 35 Mrs Smith Ch22 The delivery of nutrients to cells

36. Scholar Activity 30/11/2015Mrs Smith Ch22 The delivery of nutrients to cells 36 Try the scholar activity: http://courses.scholar.hw.ac.uk/vle/scholar/session.controller?action=v iewContent&contentGUID=ae01a001-7a3a-b119-c268-9aa0c7ae8160

37. Answers: Scholar Activity 30/11/2015Mrs Smith Ch22 The delivery of nutrients to cells 37 Try the scholar activity: http://courses.scholar.hw.ac.uk/vle/scholar/session.controller?action=v iewContent&contentGUID=ae01a001-7a3a-b119-c268-9aa0c7ae8160

38. Image source:.biomed.brown.edu.biomed.brown.edu 5. Role of the Liver in Metabolism A. Carbohydrate metabolism A nimals gain glucose by eating carbohydrates. The liver regulates the concentration of the glucose in the blood (blood sugar). After a carbohydrate rich meal, blood entering the liver by the hepatic portal vein contains a concentration of glucose in excess of the bodies immediate requirements. In response to the hormone insulin from the pancreas, an enzyme in the liver promotes the conversion glucose to glycogen 30/11/2015 38Mrs Smith Ch22 The delivery of nutrients to cells

39. Image source:.biomed.brown.edu.biomed.brown.edu 5. Role of the Liver in Metabolism A. Carbohydrate metabolism Up to 100g of excess glucose is stored in the liver as glycogen. Any more excess glucose is stored as lipids in the body’s fat reserves. If glucose is needed the glycogen breaks down releasing the glucose into the bloodstream. When the blood’s sugar level is low, a different hormone called glucagon is secreted by the pancreas. This activates a different enzyme in the liver which promotes the conversion of glycogen to glucose. Glucose is then released into the blood stream for use by living cells. GlucoseGlycogen Insulin Glucagon

40. Liver cells remove certain lipid molecules from blood and alter them to make other lipids e.g. cholesterol. Cholesterol in cell membranes needed to make steroid hormones are synthesised in liver Excess cholesterol is processed by the liver & excreted in bile Lipoproteins - formed in the liver 5. Role of the Liver in Metabolism B. Lipids 30/11/201540Mrs Smith Ch22 The delivery of nutrients to cells

41. Image sources: www.nlm.nih.govwww.nlm.nih.gov Fat-soluble vitamins are stored in liver cells e.g. Vitamins A, D, E & K 30/11/201541Mrs Smith Ch22 The delivery of nutrients to cells

42. Image sources: www.nlm.nih.govwww.nlm.nih.gov 30/11/201542Mrs Smith Ch22 The delivery of nutrients to cells

43. Image sources: www.nlm.nih.govwww.nlm.nih.gov 43

44. 3 types of plasma proteins are made in the liver. The amino acids needed for this are absorbed from the bloodstream by liver cells. Transaminase enzymes in liver cells can convert one amino acid to another. So even when amino acids aren’t obtained from food, many can be synthesised by the liver cells. Albumins Cause osmotic return of water from tissue fluid in capillary beds Globulins Cause transport of lipids and fat-soluble vitamins Fibrinogen Have an essential role in clotting of blood. 5. Role of the Liver in Metabolism C. Proteins 30/11/201544Mrs Smith Ch22 The delivery of nutrients to cells

45. 6. Fate of absorbed materials MaterialUse In BodyFate of Excess Carbohydrate Glucose used by cells to obtain energy (for aerobic respiration) Stored as glycogen in liver and muscles as fat in fatty tissues Lipids Used by cells as a source of energy Converted back to lipid & stored in fatty (adipose) tissue Proteins Amino acids used for protein synthesis (e.g. to produce enzymes, hormones, antibodies) NOT STORED some used as an energy source by cells following deamination in liver (converted to urea) 30/11/201545Mrs Smith Ch22 The delivery of nutrients to cells

46. Metal ions Zinc Iron Copper Magnesium Enzyme activators Some vitamins & minerals absorbed from food play a key role in enzyme reactions: = Co-factors Iron = the co-factor responsible for activating the enzyme catalase. Co-enzyme = a small non-protein co-factor composed of an organic substance (e.g. a vitamins). Vitamin B = an essential component of co-enzymes: acts as hydrogen carriers during aerobic respiration 6. Fate of absorbed materials D. Vitamins & minerals 30/11/201546Mrs Smith Ch22 The delivery of nutrients to cells

47. 1.What is the function of villi? 2.What is the name given to the central lymph vessel in a villus? 3.Which foodstuffs are transported by lacteals. 4.What substances are required for the proper absorption of vit B 12. 5.What is the name of the process in which amino acids are broken down in the liver? 6.What is the toxic end-product of this process? 7.Where is bile stored? 8.What is the prime function of bile? 9.What vitamins can be stored in the liver? 30/11/2015Mrs Smith Ch22 The delivery of nutrients to cells 47

48. 1.To increase the surface area of the small intestine for the absorption of food. 2.Lacteal 3.Fats. 4.Intrinsic Factor 5.Deamination 6.Urea 7.In the gall bladder 8.Bile emulsifiers (breaks up) fats. 9.A,B 12 and D 30/11/2015Mrs Smith Ch22 The delivery of nutrients to cells 48

49. Label the diagram best you can to describe the blood flow to the Liver 30/11/201549

50. Liver – Morton sheet 30/11/201550 Pulmonary ArteryPulmonary Vein Vena cava Hepatic Vein Aorta Hepatic Artery Hepatic Portal Vein

51. Label A, B and C and organ X, try other bits if you can 30/11/201551

52. Class Worksheet 30/11/201552Mrs Smith Ch22 The delivery of nutrients to cells Gall bladder Hepatic Vein Vena Cava Hepatic Artery Aorta Hepatic Portal Vein

53. Essay Questions: 2005 Describe the functions of the liver under the following headings 1.Production of urea. (2) 2.Metabolism of carbohydrates. (5) 3.Breakdown of red blood cells. (3) 30/11/2015Mrs Smith Ch22 The delivery of nutrients to cells 53

54. Task: Torrance-TYK pg172 Qu 1-4 30/11/201554Mrs Smith Ch22 The delivery of nutrients to cells

55. Task: Torrance AYK pg173-4 Qu’s 1-4 30/11/201555Mrs Smith Ch22 The delivery of nutrients to cells

56. 30/11/2015Mrs Smith Ch22 The delivery of nutrients to cells 56 Humour?