Chapter 18 Digestive System Digestive System Food must be converted by physical andchemical changes before it can be used bythe cells; this process is called digestion Enzymes Alimentary canal Accessory organs Layers of the Digestive System
Mucosa Innermost lining Submucosa Circular muscle Longitudinal muscle Lining of the Digestive System
Peritoneum Parietal Visceral Mesentery Greater omentum Peritonitis Functions of the Digestive System
Break down food physically Change food chemically Absorb the nutrients Eliminate the waste products of digestion Organs of Digestion Mouth (oral or buccal cavity)
Tongue/accessory organ of digestion Salivary glands Teeth/Accessory Organ of Digestion
Gingivae or gums Teeth Food chewed or masticated Deciduous and permanent teeth Structure of the tooth Esophagus Muscular tube to transport swallowed food to stomach
Esophageal wall layers Mucosa Submucosa Muscular External serous Stomach Fundus Body or great curvature Pylorus Upper part
Middle section Pylorus Lower portion Stomach Sphincters Four layers of the stomach wall Cardiac sphincter
Pyloric sphincter Four layers of the stomach wall Gastric Juices Enteroendocrine glands Parietal cells Chief type cells
Secrete gastrin Parietal cells Produce HCL and intrinsic factor Chief type cells Produce pepsinogen Gastric Juices Mucus cells Rennin Secrete alkaline mucus
Found in infants and children Small Intestine About 20 feet long Same four layers as the stomach
Duodenum Jejunum Ileum Digestive Juices in the Small Intestine
Enzymes, secretin, and cholecystokinin Pancreatic juices Bile Intestinal juices Absorption in the Small Intestine
Villi Makes absorption possible Each villi contains a network of blood andlymph capillaries Digested portion passes through the villi intothe bloodstream and lacteals Absorption in the Small Intestine
Undigested portion passes on to the largeintestine Accessory Organs of Digestion
Pancreas Liver Gallbladder Large Intestine Also called the colon About 5 feet long
Ileum empties chyme through ileocecal valve into large intestine Secretes mucus to lubricate passageway Large Intestine Cecum and appendix
Ascending, transverse, and descending colon Sigmoid colon Anal canal Digestive System Structures General Overview of Digestion
Bolus Peristalsis Digestion of protein, fats, and carbohydrates Absorption of nutrients Undigested substance - feces General Overview of Digestion
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 Action in the Large Intestine
Absorption Bacterial action Gas formation Fecal formation Defecation Metabolism Within the cells, nutrients are changed into energy
Aerobic metabolism Oxidation Anaerobic metabolism Krebs cycle Metabolism Anabolism and catabolism Thyroid hormones Click here to play Digestion animation
Animation Digestion Click here to play Digestion animation Effects of Aging Decrease sensory ability of taste buds
Reduction of saliva Loss of teeth Slowing peristalsis Disorders Digestive System
Stomatitis Gingivitis Periodontal disease Gastroesophageal reflux disease (GERD) Disorders Digestive System
Hiatal hernia Heartburn Pyloric stenosis Gastritis Gastroenteritis Disorders Digestive System
Enteritis Ulcer Inflammatory bowel disease (IBD) Appendicitis Hepatitis Disorders Digestive System
Cirrhosis Cholecystitis Gallstones Pancreatitis Diverticulosis Disorders Digestive System
Hemorrhoids Diarrhea Constipation