© 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

© 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

© 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)

© 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

© 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

© 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

© 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

© 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

© 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

© 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

© 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

© 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

© 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

© 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

© 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

© 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)

© 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

© 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

© 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

© 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

© 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

© 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 Liver, gallbladder, and pancreas

© 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

© 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

© 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 The structure of the large intestine

© 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

© 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

© 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

© 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

© 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

© 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

© 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

© 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)

© 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

© 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

© 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

© 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