Chapter 18 Digestive System 2017 Cengage 2017 Learning

Chapter 18 Digestive System © 2017 Cengage © 2017 Learning. Cengage All. Learning. Rights Reserved. All Rights. May Reserved. not be scanned, May not be copied scanned, copied or duplicated, or or duplicated, posted toor a publicly posted to accessible a publiclywebsite, accessible in whole website, or in in part. 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 18 -10 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 18 -11 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 © 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.