1. © 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Chapter 18 Digestive System

2. © 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Digestive System Food must be converted by physical and chemical changes before it can be used by the cells; this process is called digestion Enzymes Alimentary canal Accessory organs

3. © 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Layers of the Digestive System (1 of 2) Mucosa –Innermost lining Submucosa Muscularis − Skeletal and smooth muscle Serosa (visceral peritoneum)

4. © 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Lining of the Digestive System (2 of 2) Peritoneum –Parietal –Visceral –Mesentery –Greater omentum Peritonitis

5. © 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Functions of the Digestive System Break down food physically Peristalsis Change food chemically Absorb the nutrients Eliminate the waste products of digestion

6. © 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Figure 18-1 Structures of the digestive system

7. © 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Organs of Digestion Mouth (oral or buccal cavity) Tongue/accessory organ of digestion Salivary glands

8. © 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Teeth/Accessory Organ of Digestion Gingivae or gums Teeth –Food chewed or masticated –Deciduous and permanent teeth Structure of the tooth

9. © 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Figure 18-2 Structures of the tongue and oral cavity

10. © 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Esophagus Muscular tube to transport swallowed food to stomach Esophageal wall layers –Mucosa –Submucosa –Muscular –External serous

11. © 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Stomach (1 of 2) Fundus –Upper part Body or great curvature –Middle section Pylorus –Lower portion

12. © 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Stomach (2 of 2) Sphincters –Cardiac sphincter –Pyloric sphincter Four layers of the stomach wall

13. © 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Figure 18-5 The parts of the stomach

14. © 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Gastric Juices (1 of 2) Enteroendocrine glands –Secrete gastrin- stimulates production of HCL and pepsinogen Parietal cells –Produce HCL and intrinsic factor, converts pepsinogen into pepsin Chief type cells –Produce pepsinogen

15. © 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Gastric Juices (2 of 2) Mucus cells –Secrete alkaline mucus which neutralizes HCL Rennin –Found in infants and children

16. © 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Small Intestine About 20 feet long Same four layers as the stomach Duodenum (first segment-12 inches) Jejunum (middle segment-8 feet long) Ileum (last segment-10–12 feet)

17. © 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Figure 18-6 Small intestine

18. © 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Digestive Juices in the Small Intestine Enzymes, secretin, and cholecystokinin Pancreatic juices, protease and lipase Bile Intestinal juices

19. © 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Absorption in the Small Intestine Villi –Makes absorption possible –Increases the surface area Each villi contains a network of blood and lymph capillaries Digested portion passes through the villi into the bloodstream and lacteals Undigested portion passes on to the large intestine

20. © 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Accessory Organs of Digestion Pancreas Liver Gallbladder

21. © 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Figure 18-9 The structure of the pancreas, showing both exocrine and endocrine portions

22. © 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Figure 18-10 Liver, gallbladder, and pancreas

23. © 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Large Intestine (1 of 2) Also called the colon About 5 feet long Ileum empties chyme through ileocecal valve into large intestine Haustra are pockets that increase surface area Secretes mucus to lubricate passageway

24. © 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Large Intestine (2 of 2) Cecum and appendix Ascending, transverse, and descending colon Sigmoid colon Anal canal

25. © 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Figure 18-11 The structure of the large intestine

26. © 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. General Overview of Digestion (1 of 2) Bolus Peristalsis Digestion of protein, fats, and carbohydrates Absorption of nutrients Undigested substance – feces

27. © 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. General Overview of Digestion (2 of 2) Action in the mouth Action in the pharynx Action in the esophagus Action in the stomach Action in the small intestine Action in the large intestine

28. © 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Action in the Large Intestine Absorption Bacterial action Gas formation Fecal formation Defecation

29. © 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Effects of Aging Decrease sensory ability of taste buds Reduction of saliva Loss of teeth Slowing peristalsis

30. © 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Metabolism (1 of 2) Within the cells, nutrients are changed into energy Aerobic metabolism –Oxidation Anaerobic metabolism –Krebs cycle

31. © 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Metabolism (2 of 2) Anabolism and catabolism Thyroid hormones

32. © 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Common Symptoms of Digestive Disorders Nausea Vomiting Constipation Diarrhea

33. © 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Disorders of the Digestive System (1 of 5) Cleft lip/palate Gingivitis Periodontal disease Gastroesophageal reflux disease (GERD)

34. © 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Disorders of the Digestive System (2 of 5) Hiatal hernia Heartburn Pyloric stenosis Gastritis Gastroenteritis

35. © 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Disorders of the Digestive System (3 of 5) Enteritis Ulcer Inflammatory bowel disease (IBD) Appendicitis Hepatitis

36. © 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Disorders of the Digestive System (4 of 5) Cirrhosis Cholecystitis Gallstones Pancreatitis Diverticulosis

37. © 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Disorders of the Digestive System (5 of 5) Hemorrhoids Cancer –Stomach –Colorectal