DIGESTIVE SYSTEM Chapter 18

© 2004 Delmar Learning, a Division of Thomson Learning, Inc. LINING OF THE DIGESTIVE SYSTEM Peritoneum - two-layered membrane –Mesentery - part that attaches to posterior wall of abdominal cavity –Greater omentum - anterior portion that protects abdominal organs

© 2004 Delmar Learning, a Division of Thomson Learning, Inc. FUNCTIONS OF THE DIGESTIVE SYSTEM Break food into smaller pieces Change food chemically into fat, carbohydrates, and protein Absorb nutrients into blood capillaries of small intestines Eliminate waste products of digestion

© 2004 Delmar Learning, a Division of Thomson Learning, Inc. ORGANS OF DIGESTION

© 2004 Delmar Learning, a Division of Thomson Learning, Inc. ORGANS OF DIGESTION Many organs contribute to digestion –Mouth –Tongue –Salivary glands

© 2004 Delmar Learning, a Division of Thomson Learning, Inc. ORGANS OF DIGESTION

© 2004 Delmar Learning, a Division of Thomson Learning, Inc. TEETH/ ACCESSORY ORGAN OF DIGESTION Structure of a tooth –Crown –Neck –Root –Periodontal membrane –Pulp cavity –Dentin –Enamel

© 2004 Delmar Learning, a Division of Thomson Learning, Inc. ESOPHAGUS The esophagus is a muscular tube beginning at the lower end of the pharynx, passing through the diaphragm and connecting to the upper portion of the stomach

© 2004 Delmar Learning, a Division of Thomson Learning, Inc. STOMACH Stomach is divided into 3 portions –Fundus - upper part –Greater curvature (body) - middle –Pylorus - lower portion Gastric juices are secreted by millions of gastric glands

© 2004 Delmar Learning, a Division of Thomson Learning, Inc. SMALL INTESTINE The final preparation of food to be absorbed occurs in the small intestine Divided into three sections –Duodenum –Jejunum –Ileum

© 2004 Delmar Learning, a Division of Thomson Learning, Inc. SMALL INTESTINE Digestive juices –Enzymes, secretin, cholecystokinin stimulate digestive juices –Pancreatic juices break down food –Bile emulsifies fat –Intestinal juices break food down further for absorption

© 2004 Delmar Learning, a Division of Thomson Learning, Inc. SMALL INTESTINE Absorption in the small intestine is accomplished through millions of villi. The indigestible portion is passed through to the large intestine

© 2004 Delmar Learning, a Division of Thomson Learning, Inc. LIVER/ACCESSORY ORGAN OF DIGESTION Functions of the liver –Manufactures bile which is necessary for fat digestion –Produces and stores glucose in the form of glucogen –Detoxifies alcohol, drugs and other harmful substances –Manufactures blood proteins

© 2004 Delmar Learning, a Division of Thomson Learning, Inc. LIVER/ACCESSORY ORGAN OF DIGESTION Prepares urea, the chief waste product of protein metabolism Stores vitamins A, D, and B complex Breaks down hormones no longer useful to the body Removes old red blood cells and recycles iron content

© 2004 Delmar Learning, a Division of Thomson Learning, Inc. GALLBLADDER The gallbladder stores and concentrates bile when it is not needed by the body

© 2004 Delmar Learning, a Division of Thomson Learning, Inc. LARGE INTESTINE Chyme is semi-liquid food in the large intestine Colon –Ascending –Traverse –Descending Anal Canal

© 2004 Delmar Learning, a Division of Thomson Learning, Inc. GENERAL OVERVIEW OF DIGESTION Mouth Pharynx Esophagus Stomach Small Intestine Large Intestine

© 2004 Delmar Learning, a Division of Thomson Learning, Inc. COMMON DISORDERS OF THE DIGESTIVE SYSTEM Stomatitis Gastroesophageal reflux disease Hiatal hernia Heartburn Gastritis Gastoenteritis Enteritis

© 2004 Delmar Learning, a Division of Thomson Learning, Inc. COMMON DISORDERS OF THE DIGESTIVE SYSTEM Ulcer Inflammatory bowel disease Appendicitis Hepatitis Cirrhosis Cholecystitis Gallstones

© 2004 Delmar Learning, a Division of Thomson Learning, Inc. COMMON DISORDERS OF THE DIGESTIVE SYSTEM Pancreatitis Diverticulosis Diarrhea Constipation Stomach cancer Colon cancer