Chapter 15 Lecture and Animation Outline

Transcription

1 Chapter 15 Lecture and Animation Outline To run the animations you must be in Slideshow View. Use the buttons on the animation to play, pause, and turn audio/text on or off. Please Note: Once you have used any of the animation functions (such as Play or Pause), you must first click on the slide s background before you can advance to the next slide. See separate PowerPoint slides for all figures and tables preinserted into PowerPoint without notes and animations. Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 1

2 15.1 Anatomy of the digestive system 2

3 A. Introduction 1. Also called the alimentary canal or gastrointestinal (GI) tract 2. Digestion includes both physical and chemical processes that reduce food into soluble molecules that can be absorbed into the blood stream 3. Functions of the digestive system: a. Ingest food b. Break food down into small molecules c. Absorb nutrient molecules d. Eliminate non-digestible wastes 3

4 Structures of the digestive system 4

5 Digestive System Overview Please note that due to differing operating systems, some animations will not appear until the presentation is viewed in Presentation Mode (Slide Show view). You may see blank slides in the Normal or Slide Sorter views. All animations will appear after viewing in Presentation Mode and playing each animation. Most animations will require the latest version of the Flash Player, which is available at 5

6 B. The mouth (oral cavity) 1. Tongue a. Composed of skeletal muscle b. Papillae 1) Help it handle food 2) Contain taste buds c. Lingual frenulum attaches it to the floor of the mouth 2. Roof separates the oral cavity from the nasal cavities a. Hard palate b. Soft palate 6

7 C. Teeth and salivary glands 1. Teeth a. 20 deciduous (baby) teeth b. 32 adult teeth embedded in the maxilla and mandible 1) 4 incisors per jaw 2) 2 cuspids (canines) per jaw 3) 4 bicuspids per jaw 4) 6 molars per jaw 7

8 Teeth, cont. c. Tooth structure 1) Crown layers of enamel, dentin, and pulp 2) Root layers of cementum, dentin, and pulp d. Diseases 1) Caries occur when bacteria break down sugars and produce acids that erode the enamel 2) Gum diseases are more likely as we age gingivitis and periodontitis 8

9 Human teeth 9

10 2. Salivary glands a. Salivary glands 1) Parotid 2) Sublingual 3) Submandibular b. Saliva solution of mucus and water 1) Salivary amylase begins the process of digesting carbohydrates 2) Moistens food and prepares it for swallowing 3) Antibacterial lysozyme and secretory antibodies 10

11 D. The pharynx 1. Passageway for food and air 2. Three parts a. Nasopharynx - air b. Oropharynx food and air c. Laryngopharynx - food 3. Tonsils a. Palatine tonsils b. Lingual tonsils c. Pharyngeal tonsil (adenoids) 11

12 E. Swallowing 1. Begins with the voluntary phase 2. Reflex action once food or drink is pushed back to the oropharynx 3. Bolus chewed and swallowed food or drink 12

13 Swallowing 13

14 F. The Wall of the Digestive Tract 1. Mucosa (mucous membrane layer) a. Layer of epithelium that lines the lumen b. Glandular epithelial cells secrete digestive enzymes c. Goblet cells secrete mucus 2. Submucosa (submucosal layer) a. Loose connective tissue b. Contains blood vessels, lymphatic vessels, and nerves c. Peyer s patches are scattered throughout the submucosa of the small intestine 14

15 Wall layers, cont 3. Muscularis (smooth muscle layer) a. Inner, circular layer b. Outer, longitudinal layer c. The stomach has an extra oblique layer 4. Serosa (serous membrane layer) a. Thin, outermost layer of squamous epithelium b. Secretes serous fluid c. Adventitia outer connective tissue layer of the esophagus 15

16 Wall of the alimentary canal 16

17 G. The esophagus 1. Muscular tube from the pharynx to the stomach 2. Peristalsis pushes food along the alimentary canal 3. Function is to transport food to the stomach; no chemical digestion 4. Esophageal sphincter marks the entrance to the stomach 5. Heartburn occurs when some of the stomach contents escapes into the esophagus; GERD chronic reflux disorder 17

18 Peristalsis 18

19 H. The stomach 1. Thick-walled, J-shaped organ on the left side of the abdominal cavity 2. Continuous with the esophagus and duodenum of the small intestine 3. Rugae deep folds in its wall 4. Functions a. Stores and liquefies food b. Starts the digestion of proteins c. Moves food into the small intestine 19

20 5. Regions of the stomach a. Cardiac stomach b. Fundic stomach c. Body of the stomach d. Pyloric stomach 20

21 Anatomy & histology of the stomach 21

22 6. Digestive functions of the stomach a. Acts on food both chemically and physically b. Muscular wall churns and mixes food with gastric juice c. Gastric pits lead to gastric glands that produce gastric juice d. Alcohol and water are absorbed through the stomach wall e. Churned food and gastric juice mixture is called chyme which leaves the stomach in 2 to 6 hours f. Ulcer open sore, mainly caused by the bacterium, Helicobacter pylori 22

23 g. Makeup of gastric juice 1) Chief cells a) Secrete pepsinogen b) Pepsinogen becomes the proteindigesting enzyme pepsin when activated by HCl 2) Parietal cells a) Produce hydrochloric acid kills bacteria and activates pepsin b) Produces intrinsic factor binds to vitamin B 12 and prevents it from being destroyed in the acidic environment 23

24 Gastric juice, cont 3) Enteroendocrine cells produce gastrin that regulates muscular contractions and secretions of the stomach 4) Mucous cells secrete protective mucus 5) ECL cells release histamine to enhance the action of gastrin 24

25 Stomach Please note that due to differing operating systems, some animations will not appear until the presentation is viewed in Presentation Mode (Slide Show view). You may see blank slides in the Normal or Slide Sorter views. All animations will appear after viewing in Presentation Mode and playing each animation. Most animations will require the latest version of the Flash Player, which is available at 25

26 Hydrochloric Acid Production Please note that due to differing operating systems, some animations will not appear until the presentation is viewed in Presentation Mode (Slide Show view). You may see blank slides in the Normal or Slide Sorter views. All animations will appear after viewing in Presentation Mode and playing each animation. Most animations will require the latest version of the Flash Player, which is available at 26

27 I. Peritoneum 1. Serous membrane of the abdominal cavity 2. Parietal peritoneum lines the abdominal wall 3. Visceral peritoneum covers the organs a. Lesser omentum mesentery that runs between the stomach and liver b. Greater omentum mesentery that hangs down in front of the intestines 1) Cushions and insulates the abdominal cavity 2) Contains macrophages 3) Can wall off portions of the alimentary wall that may be infected 27

28 Function of the mesentery 28

29 J. The small intestine 1. Extends from the pyloric valve of the stomach to the ileocecal valve where it joins the large intestine (about 18 ft in a cadaver) 2. Regions of the Small Intestine a. Duodenum many folds and villi 1) Glands secrete mucus 2) Receives pancreatic secretions and bile b. Jejunum c. Ileum contains Peyer s patches with few folds and villi 29

30 Regions of the small intestine 30

31 3. Wall of the small intestine a. Wall is modified to greatly increase surface area b. Circular folds permanent transverse folds c. Villi finger-like projections containing blood capillaries and a lacteal (lymphatic capillary) d. Microvilli microscopic extensions of the columnar cells; called the brush border 31

32 Anatomy of the small intestine 32

33 4. Functions of the small intestine a. Digestion of fats, proteins, and carbohydrates into soluble molecules 1) Bile and pancreatic enzymes enter the duodenum for chemical digestion 2) Intestinal enzymes complete chemical digestion b. Absorption of nutrients 1) Sugars and amino acids enter the blood 2) Glycerol and fatty acids enter the lacteal c. Movement of nondigested remains to the large intestine 1) Segmentation 2) Peristalsis 33

34 5. Regulation of contraction and secretion a. The central nervous system allows a response to hunger signals b. Enteric nervous system - a network of nerves within the walls of the GI tract that controls its own movements and secretions c. Autonomic nervous system 1) Parasympathetic division is the major controller of digestive activities 2) Sympathetic division slows digestive activities 34

35 d. Nervous control 1) Cephalic phase - Sight or smell of food causes parasympathetic stimulation of gastric secretion 2) Gastric phase stretch of the stomach causes gastric contraction and secretion by gastric glands including gastrin 3) Intestinal phase stretch of the duodenum causes contraction and secretion in the small intestine and feeds back to the stomach 35

36 Three Phases of Gastric Secretion Please note that due to differing operating systems, some animations will not appear until the presentation is viewed in Presentation Mode (Slide Show view). You may see blank slides in the Normal or Slide Sorter views. All animations will appear after viewing in Presentation Mode and playing each animation. Most animations will require the latest version of the Flash Player, which is available at 36

37 e. Hormonal control 1) Gastrin - causes gastric contraction and secretion by gastric glands 2) Secretin causes bicarbonate release from pancreas & liver production of bile 3) Gastric inhibitory peptide (GIP) inhibits gastric action & slows contractions 4) Cholecystokinin (CCK) causes enzyme release from pancreas & gall bladder release of bile 5) Leptin from adipocytes, causes full feeling 6) Ghrelin from stomach, triggers hunger 37

38 Hormonal control of secretion 38

39 K. The large intestine 1. Has a larger diameter but is shorter than the small intestine 2. Functions a. Absorbs water, salts, and some vitamins b. Stores indigestible material until it is eliminated 3. Regions a. Cecum - blind sac below ileocecal valve; vermiform appendix is attached b. Colon - ascending colon, transverse colon, descending colon, sigmoid colon 1) Haustra 2) Taenia coli c. Rectum d. Anal canal 39

40 The large intestine 40

41 Large intestine, cont 4. Feces a. 75% water b. 25% solids 1) Bacteria 2) Fiber and other indigestible remains c. Color comes from a breakdown product of bilirubin 5. Colon bacteria feed on cellulose and produce fatty acids, B-complex vitamins, vitamin K, and gases that contribute to flatus 41

42 6. Defecation reflex a. Rectal muscles contract and relax the internal anal sphincter b. Feces move into the anal canal c. Voluntary relaxation of the external anal sphincter and a pushing movement, propels the feces from the body d. There is much variation in the frequency of defecation 42

43 Reflexes of the Colon Please note that due to differing operating systems, some animations will not appear until the presentation is viewed in Presentation Mode (Slide Show view). You may see blank slides in the Normal or Slide Sorter views. All animations will appear after viewing in Presentation Mode and playing each animation. Most animations will require the latest version of the Flash Player, which is available at 43

44 7. Irregular bowel movements a. Constipation 1) Slow movement with more absorption of water 2) Feces are dry and hard 3) Chronic constipation is associated with hemorrhoids b. Diarrhea 1) Fast movement with not enough water reabsorbed 2) Caused by infection of the lower intestinal tract or irregular nervous stimulation 44

45 8. Other disorders of the large intestine a. Polyps 1) Small growths arising from the epithelial lining of the colon 2) Can be benign or cancerous (colon cancer) b. Diverticulosis 1) Presence of saclike pouches 2) Diverticulitis inflammation occurs a) Cramps or steady pain b) Fever c) Loss of appetite, nausea, and vomiting 45

46 15.2 Accessory organs of digestion Teeth and salivary glands were covered with the oral cavity 46

47 A. Pancreas 1. Endocrine function pancreatic islets secrete insulin, glucagon, and somatostatin 2. Exocrine function acinar cells produce pancreatic juice a. Sodium bicarbonate to neutralize acidic chyme b. Digestive enzymes for all types of foods 1) Amylase digests starch 2) Three protein-digesting enzymes released in inactive forms a) Trypsin activated by enterokinase b) Chymotrypsin and Carboxypeptidase activated by trypsin 3) Lipase digests fat 4) Nucleases break down nucleic acids 47

48 The pancreas 48

49 B. The liver 1. Liver Structure a. Two main lobes b. Each lobe is divided into many hepatic lobules 1) Hepatic cells 2) Hepatic sinusoids 3) Kupffer cells phagocytic macrophages c. Portal triads are located between the lobules 1) Bile duct 2) A branch of the hepatic artery 3) A branch of the hepatic portal vein 49

50 Liver structure, cont d. Bile ducts merge to form the common hepatic duct e. Central veins from each lobule enters a hepatic vein 50

51 Liver anatomy 51

52 2. Liver functions a. Detoxifies blood b. Removes and stores nutrients c. Stores iron and vitamins A, D, E, and K d. Makes plasma proteins e. Maintains blood glucose concentrations 1) Insulin stores glucose as glycogen (glycogenesis) 2) Glucagon breaks down glycogen to glucose (glycogenolysis) 3) New glucose made from other molecules (gluconeogenesis) 52

53 Liver functions, cont f. Produces urea after breaking down amino acids g. Forms and secretes bile h. Helps regulate the blood cholesterol level 53

54 Liver Please note that due to differing operating systems, some animations will not appear until the presentation is viewed in Presentation Mode (Slide Show view). You may see blank slides in the Normal or Slide Sorter views. All animations will appear after viewing in Presentation Mode and playing each animation. Most animations will require the latest version of the Flash Player, which is available at 54

55 3. Liver disorders a. Jaundice yellow tint to the whites of the eyes and skin due to bilirubin deposits 1) Hemolytic jaundice 2) Obstructive jaundice 3) Hepatitis b. Cirrhosis liver becomes fatty and then liver tissue is replaced by fibrous scar tissue 55

56 C. The gallbladder 1. Sac on the inferior surface of the liver that stores and concentrates excess bile 2. When needed, bile leaves the gallbladder via the cystic duct 3. The cystic duct joins the common hepatic duct to form the common bile duct that enters the duodenum with the pancreatic duct 4. Function of bile salts a. Emulsification of fats b. Enhance absorption of fatty acids, cholesterol, and fat soluble vitamins 56

57 15.3 Chemical Digestion 57

58 A. Digestive enzymes 1. Digestive enzymes are hydrolytic enzymes 2. Break down substances with the addition of water at specific bonds 3. Have an optimum ph to function at 58

59 B. Carbohydrates 1. Salivary amylase breaks carbohydrates into maltose 2. Action stops in the stomach (too acidic) 3. Pancreatic amylase continues the hydrolysis to maltose 4. Brush border enzymes of the small intestine break down disaccharides to monosaccharides (mainly glucose) a. Sucrose broken down by sucrase b. Lactose broken down by lactase c. Maltose broken down by maltase 5. Monosaccharides are absorbed by intestinal cells into blood capillaries 59

60 Hydrolysis of Sucrose Please note that due to differing operating systems, some animations will not appear until the presentation is viewed in Presentation Mode (Slide Show view). You may see blank slides in the Normal or Slide Sorter views. All animations will appear after viewing in Presentation Mode and playing each animation. Most animations will require the latest version of the Flash Player, which is available at 60

61 Carbohydrate digestion & absorption 61

62 C. Proteins 1. Pepsin in the stomach hydrolyzes proteins into short polypeptides 2. Three pancreatic proteinases trypsin, chymotrypsin, and carboxypeptidase break down polypeptides to peptides and some amino acids 3. Peptidases (brush border enzymes) complete the digestion of peptides into amino acids in the small intestine 4. Amino acids are absorbed by intestinal cells into blood capillaries 62

63 Protein digestion & absorption 63

64 D. Fats 1. First emulsified by bile in the duodenum 2. Digested by pancreatic lipase to glycerol and fatty acids 3. Enter intestinal cells where the fatty acids are packaged as lipoproteins and then enter the lacteals 64

65 Fat digestion & absorption 65

66 E. Nucleic acids 1. Pancreatic nucleases break down DNA and RNA into nucleotides 2. Brush border nucleotidases break down the nucleotides to sugar, phosphate, and nitrogenous base 3. These chemicals enter intestinal cells into the blood capillaries 66

67 Major digestive enzymes 67

68 15.4 Effects of aging 68

69 A. Effects of Aging 1. Incidence of gastrointestinal disorders increases 2. Periodontitis 3. Esophageal hiatal hernia 4. Heartburn & GERD 5. Peristalsis slows 6. Peptic ulcers may occur more frequently 7. Diverticulosis and constipation not enough fiber 8. The liver shrinks 9. Gallbladder difficulties occur gallstones 10. Cancer 11. Hemorrhoids 12. Fecal incontinence 69

70 15.5 Homeostasis 70

71 A. Homeostasis 1. Alimentary canal is also part of the endocrine system 2. Nutrients absorbed by the alimentary canal are used for energy, growth, and repair 3. Vitamins needed for normal growth and development 4. Minerals assist in many body processes 71

72 Human Systems Working Together 72

73 15.6 Nutrition 73

74 A. Nutrition 1. Nutrition interaction between food and the living organism 2. Nutrient substance the body uses to maintain health 3. A balanced diet contains all the essential nutrients in correct proportions 4. Nutrients enter the blood and are distributed to the tissues 74

75 Nutrition, cont 5. Essential molecules must be present in food because the body is unable to produce them a. Two essential fatty acids b. Nine essential amino acids 6. Glucose is the body s immediate energy source 7. Fats are a long-term energy source 8. Amino acids used by the cells to construct proteins and can be used for energy is needed 75

76 Newest dietary guidelines Go to to personalize 76

77 B. Vitamins 1. Vital to life 2. Play essential roles in cellular metabolism 3. Fat-soluble - vitamins A, D, E, and K 4. Water-soluble a. B-complex vitamins and vitamin C b. Most are coenzymes 77

78 Vitamins 78

79 C. Minerals 1. Inorganic elements 2. Macronutrients a. Sodium b. Magnesium c. Phosphorus d. Chlorine e. Potassium f. Calcium 3. Micronutrients trace elements needed in very small amounts 79

80 Minerals 80

81 D. Eating disorders 1. Obesity a. Body weight 20% or more above the ideal weight for a person s height b. 36% of women and 32% of men in the U.S. are overweight c. Caused by a combination of factors hormonal, metabolic, and social 81

82 2. Bulimia nervosa a. Can coexist with either obesity or anorexia nervosa b. Binge eating, then purging c. Alters blood composition, leading to abnormal heart rhythm, kidney failure and even death d. Stomach acids can cause teeth to erode e. Esophagus and stomach may rupture 82

83 3. Anorexia nervosa a. Morbid fear of gaining weight b. Individuals have a distorted self-image c. Individuals have all the symptoms of starvation 1) Low blood pressure 2) Irregular heartbeat 3) Constipation 4) Constant chilliness 5) Bone density decreases 6) Menstruation stops in females 7) Internal organs do not function well 8) Skin dries up 83

84 Anorexia Nervosa & Bulimia Nervosa 84