1. Welcome to Unit 5 Chapters 15 & 16

2. Chapter 15 The Digestive System

3. Elsevier items and derived items © 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 3 DIGESTIVE SYSTEM (FIGURE 15-1)  Irregular tube called alimentary canal or gastrointestinal (GI) tract  Food must first be digested, then absorbed, and later metabolized

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6. Elsevier items and derived items © 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 6 WALL OF THE DIGESTIVE TRACT (FIGURE 15-2)  Digestive tract described as tube that extends from mouth to anus  Wall of the digestive tube is formed by four layers of tissue:  Mucosa—mucous epithelium  Submucosa—connective tissue  Muscularis—two layers of smooth muscle  Serosa—serous membrane that covers the outside of abdominal organs; it attaches the digestive tract to the wall of the abdominopelvic cavity by forming folds called mesenteries

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9. Elsevier items and derived items © 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 9 MOUTH  Roof—formed by hard palate (parts of maxillary and palatine bones) and soft palate, an arch-shaped muscle separating mouth from pharynx; uvula, a downward projection of soft palate (Figure 15-4)  Floor—formed by tongue and its muscles; papillae, small elevations on mucosa of tongue; taste buds, found in many papillae; lingual frenulum, fold of mucous membrane that helps anchor tongue to floor of mouth (Figure 15-4)  Typical tooth (Figure 15-5)  Three main parts—crown, neck, and root  Enamel, which covers the crown, is hardest tissue in body

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12. Elsevier items and derived items © 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 12 MOUTH  Types of teeth—incisors, cuspids, bicuspids, and tricuspids  Twenty teeth in temporary set; average age for cutting first tooth about 6 months; set complete at about 2 years of age  Thirty-two teeth in permanent set; 6 years about average age for starting to cut first permanent tooth; set complete usually between ages of 17 and 24 years (Figure 15-6)

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14. Elsevier items and derived items © 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc.  What is the largest salivary gland? Slide 14

15. Elsevier items and derived items © 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 15 SALIVARY GLANDS (FIGURE 15-7)  Parotid glands—largest salivary glands  Submandibular glands—open into mouth on either side of frenulum  Sublingual glands—open into floor of mouth

16. Elsevier items and derived items © 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 16

17. Elsevier items and derived items © 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 17 PHARYNX  Tubelike structure that allows both food and air to pass.

18. Elsevier items and derived items © 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc.  What connects the pharynx to the stomach? Slide 18

19. Elsevier items and derived items © 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 19 ESOPHAGUS  Connects pharynx to stomach  Dynamic passageway for food

20. Elsevier items and derived items © 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 20 STOMACH (Figure 15-8)  Size—expands after large meal; about size of large sausage when empty  Food enters stomach through gastroesophageal (cardiac) sphincter  Pyloric sphincter muscle closes opening between pylorus (lower part of stomach) and duodenum  Wall—many smooth muscle fibers; contractions produce churning movements (peristalsis)  Lining—mucous membrane; many microscopic glands that secrete gastric juice and hydrochloric acid into stomach; mucous membrane lies in folds (rugae) when stomach is empty

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22. Elsevier items and derived items © 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 22 SMALL INTESTINE (FIGURE 15-9)  Size—about 7 meters (20 feet) long but only 2 cm or so in diameter  What are the three divisions

23. Elsevier items and derived items © 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 23 SMALL INTESTINE (FIGURE 15-9)  Divisions  Duodenum  Jejunum  Ileum

24. Elsevier items and derived items © 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 24 The surface is folded and covered with villi. Can you tell what this does?

25. Elsevier items and derived items © 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 25 SMALL INTESTINE  Wall—contains smooth muscle fibers that contract to produce peristalsis  Lining—mucous membrane; many microscopic glands (intestinal glands) secrete intestinal juice; villi (microscopic finger-shaped projections from surface of mucosa into intestinal cavity) contain blood and lymph capillaries

26. Elsevier items and derived items © 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 26 LIVER AND GALLBLADDER  Size and location—liver is largest gland; fills upper right section of abdominal cavity and extends over into left side  Liver secretes bile  Ducts (Figure 15-10)  Hepatic—drains bile from liver  Cystic—duct by which bile enters and leaves gallbladder  Common bile—formed by union of hepatic and cystic ducts; drains bile from hepatic or cystic ducts into duodenum  Gallbladder  Location—undersurface of the liver  Function—concentrates and stores bile produced in the liver

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28. Elsevier items and derived items © 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc.  What does bile do? Slide 28

29. Elsevier items and derived items © 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc.  Bile acts as a detergent to mechanically break up, or emulsify fats. Slide 29

30. Elsevier items and derived items © 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc.  What is the exocrine gland that lies behind stomach? Slide 30

31. Elsevier items and derived items © 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 31 PANCREAS  Functions  Pancreatic cells secrete pancreatic juice (most important digestive juice) into pancreatic ducts; main duct empties into duodenum  Pancreatic islets (of Langerhans)—cells not connected with pancreatic ducts; secrete hormones glucagon and insulin into the blood

32. Elsevier items and derived items © 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Large Intestine  What are the three divisions? Slide 32

33. Elsevier items and derived items © 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 33 LARGE INTESTINE (FIGURE 15-12)  Divisions  Cecum  Colon—ascending, transverse, descending, and sigmoid  Rectum  Food enters through ileocecal valve; external opening called anus  Wall—contains smooth muscle fibers that contract to produce churning, peristalsis, and defecation  Lining—mucous membrane

34. Elsevier items and derived items © 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 34 ?

35. Elsevier items and derived items © 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 35 APPENDIX  Blind tube off cecum  No important digestive functions in humans

36. Elsevier items and derived items © 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 36 PERITONEUM (FIGURE 15-14)  Definitions—peritoneum, serous membrane lining abdominal cavity and covering abdominal organs; parietal layer of peritoneum lines abdominal cavity; visceral layer of peritoneum covers abdominal organs; peritoneal space lies between parietal and visceral layers  Extensions—largest are the mesentery and greater omentum  Mesentery is extension of parietal peritoneum, which attaches most of small intestine to posterior abdominal wall  Greater omentum, or “lace apron,” hangs down from lower edge of stomach and transverse colon over intestines  X-ray studies of the GI tract—radiopaque contrast medium used to help visualize structures in study images

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38. Elsevier items and derived items © 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 38 DIGESTION (TABLE 15-2)  Definition—transforms foods into substances that can be absorbed and used by cells  Mechanical digestion—chewing (mastication), swallowing (deglutition), and peristalsis break food into tiny particles, mix them well with digestive juices, and move them along the digestive tract  Chemical digestion—breaks up large food molecules into compounds that have smaller molecules; brought about by digestive enzymes (Figure 15-15)  Enzymes and chemical digestion  Enzymes are specialized protein molecules that act as catalysts  Breakdown process called hydrolysis

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40. Elsevier items and derived items © 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 40 DIGESTION  Carbohydrate digestion—mainly in small intestine  Pancreatic amylase—breaks polysaccharides down to disaccharides  Intestinal juice enzymes Maltase—changes maltose to glucose Maltase—changes maltose to glucose Sucrase—changes sucrose to glucose Sucrase—changes sucrose to glucose Lactase—changes lactose to glucose Lactase—changes lactose to glucose

41. Elsevier items and derived items © 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 41 DIGESTION  Protein digestion—starts in stomach; completed in small intestine  Gastric juice enzyme pepsin partially digests proteins  Pancreatic enzyme, trypsin, continues digestion of proteins  Intestinal enzymes, peptidases, complete digestion of partially digested proteins and convert them to amino acids  Fat digestion  Bile contains no enzymes but emulsifies fats (breaks fat droplets into very small droplets)  Pancreatic lipase changes emulsified fats to fatty acids and glycerol in small intestine

42. Elsevier items and derived items © 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 42 ABSORPTION  Definition—process by which digested food moves from intestine into blood or lymph  Foods and most water minerals and vitamins are absorbed from small intestine; some water and vitamin K also absorbed from large intestine  Surface area absorption  Structural adaptations increase absorptive surface area  Fractal geometry—study of fragmented geometric irregular shapes such as those in lining of intestine

43. Chapter 16 Nutrition and Metabolism

44. Elsevier items and derived items © 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 44 DEFINITIONS  Nutrition—food, vitamins, and minerals that are ingested and assimilated into the body  Metabolism—process of using food molecules as energy sources and as building blocks for our own molecules  Catabolism—breaks food molecules down, releasing their stored energy; oxygen used in catabolism  Anabolism—builds food molecules into complex substances

45. Elsevier items and derived items © 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 45 ROLE OF THE LIVER  Secretes bile, which breaks down large fat globules  Helps maintain normal blood glucose level  Helps metabolize carbohydrates, fats, and proteins; synthesizes several kinds of protein compounds  Removes toxins from the blood

46. Elsevier items and derived items © 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 46 NUTRIENT METABOLISM  Carbohydrates—preferred energy food of the body  What are the three series of chemical reactions in glucose metabolism?

47. Elsevier items and derived items © 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 47 NUTRIENT METABOLISM  Carbohydrates—preferred energy food of the body  Three series of chemical reactions in glucose metabolism Glycolysis Glycolysis  Changes glucose to pyruvic acid  Anaerobic (uses no oxygen)  Yields small amount of energy (transferred to ATP)  Occurs in cytoplasm Citric acid (Krebs) cycle Citric acid (Krebs) cycle  Changes pyruvic acid to carbon dioxide  Aerobic (requires oxygen)  Yields large amount of energy (mostly as high energy electrons)  Occurs in mitochondria Electron transfer system Electron transfer system  Transfers energy from high energy electrons (from citric acid cycle) to ATP molecules  Located in mitochondria

48. Elsevier items and derived items © 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 48 NUTRIENT METABOLISM  Carbohydrates (cont.)  Carbohydrates are primarily catabolized for energy (Figure 16-1), but small amounts are anabolized by glycogenesis (a series of chemical reactions that changes glucose to glycogen—occurs mainly in liver cells where glycogen is stored)  Adenosine triphosphate (ATP)—molecule in which energy obtained from breakdown of foods is stored; serves as a direct source of energy for cellular work (Figure 16-2)  Blood glucose (imprecisely, blood sugar)—normally stays between about 80 and 110 mg per 100 mL of blood during fasting; insulin accelerates the movement of glucose out of the blood into cells, therefore decreases blood glucose and increases glucose catabolism  Fats—catabolized to yield energy and anabolized to form adipose tissue (Figure 16-3)  Proteins—primarily anabolized and secondarily catabolized

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51. Elsevier items and derived items © 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 51 Catabolism of nutrients

52. Elsevier items and derived items © 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 52 VITAMINS AND MINERALS  Vitamins—organic molecules that are needed in small amounts for normal metabolism (Table 16-2)  Minerals—inorganic molecules found naturally in the earth, required by the body for normal function (Table 16-3)

53. Elsevier items and derived items © 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 53 METABOLIC RATES  Basal metabolic rate (BMR)—rate of metabolism when a person is lying down but awake and not digesting food and when the environment is comfortably warm  Total metabolic rate (TMR)—the total amount of energy, expressed in calories, used by the body per day (Figure 16-4)

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55. Elsevier items and derived items © 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Slide 55 BODY TEMPERATURE  Hypothalamus—regulates the homeostasis of body temperature (thermoregulation) through a variety of processes  Skin—can cool the body by losing heat from the blood through four processes: radiation, conduction, convection, evaporation (Figure 16-5)

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57. Elsevier items and derived items © 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc.  Questions?? Slide 57