Copyright © 2004 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 6:11 Digestive System Also known as the gastrointestional system Responsible for the physical and chemical breakdown of food for use by the body Alimentary canal Tube from the mouth to the anus Consists of the mouth, pharynx, esophagus, stomach, small & large intestine, & anus Copyright © 2004 by Thomson Delmar Learning. ALL RIGHTS RESERVED.

Copyright © 2004 by Thomson Delmar Learning. ALL RIGHTS RESERVED. Mouth Also referred to as oral cavity or buccal cavity Teeth: responsible for the mechanical breakdown of food (mastication) Saliva: lubricates & partially digests food Tongue: aids in tasting, chewing, and swallowing of food Hard palate: “roof of the mouth” Soft palate: separates the mouth from the nasopharynx Uvula: prevents food from entering the nasopharynx during swallowing Salivary glands: produce saliva Copyright © 2004 by Thomson Delmar Learning. ALL RIGHTS RESERVED.

Copyright © 2004 by Thomson Delmar Learning. ALL RIGHTS RESERVED. Pharynx (Throat) Carrier for both air to the trachea and food to the esophagus Carries food bolus (food mixed with saliva) to the esophagus When bolus swallowed, epiglottis closes to prevent food from entering respiratory tract Copyright © 2004 by Thomson Delmar Learning. ALL RIGHTS RESERVED.

Copyright © 2004 by Thomson Delmar Learning. ALL RIGHTS RESERVED. Esophagus Muscular tube dorsal to (behind) the trachea Carries bolus to stomach Peristalsis: rhythmic, wavelike, involuntary movement of muscles that pushes food into the stomach Copyright © 2004 by Thomson Delmar Learning. ALL RIGHTS RESERVED.

Copyright © 2004 by Thomson Delmar Learning. ALL RIGHTS RESERVED. Stomach Receives food from esophagus Lined with a mucous membrane lining contain rugae (folds) that expand when filled with food Cardiac sphincter (or lower esophageal sphincter): circular muscle between esophagus & stomach that closes to keep food from going back up into the esophagus Copyright © 2004 by Thomson Delmar Learning. ALL RIGHTS RESERVED.

Copyright © 2004 by Thomson Delmar Learning. ALL RIGHTS RESERVED. Stomach (cont) Pyloric sphincter: circular muscle between stomach & small intestine that closes to keep food in the stomach until it is ready to enter the small intestine Food remains in stomach about 1-4 hours Gastric juices: contain hydrochloric acid that kills bacteria, and aids in the breakdown of food Copyright © 2004 by Thomson Delmar Learning. ALL RIGHTS RESERVED.

Copyright © 2004 by Thomson Delmar Learning. ALL RIGHTS RESERVED. Small Intestine About 20 feet long; 1 inch in diameter Receives food from the stomach in the form of chyme (semiliquid material of broken down food) 3 sections: Duodenum Jejunum Ileum Copyright © 2004 by Thomson Delmar Learning. ALL RIGHTS RESERVED.

Small Intestine (continued) Contain enzymes (juices) that complete the digestive process Bile: secreated from the liver, helps breakdown fat Pancreatic juic When exits small intestine, only wastes, indigestible materials, and excess water remain Copyright © 2004 by Thomson Delmar Learning. ALL RIGHTS RESERVED.

Copyright © 2004 by Thomson Delmar Learning. ALL RIGHTS RESERVED. Large Intestine About 5 feet long; 2 inches in diameter Functions Absorbes water & any remaining nutrients Divided into sections: Cecum Ascending Colon Transverse Colon Descending Colon Sigmoid Colon Rectum Anus Copyright © 2004 by Thomson Delmar Learning. ALL RIGHTS RESERVED.

Copyright © 2004 by Thomson Delmar Learning. ALL RIGHTS RESERVED. Liver Largest gland in the body Located under the diaphragm in the URQ (upper right quadrant) Secretes bile to aid in the breakdown of fat Copyright © 2004 by Thomson Delmar Learning. ALL RIGHTS RESERVED.

Copyright © 2004 by Thomson Delmar Learning. ALL RIGHTS RESERVED. Gallbladder Small muscular sac Located under the liver Stores and concentrates bile Copyright © 2004 by Thomson Delmar Learning. ALL RIGHTS RESERVED.

Copyright © 2004 by Thomson Delmar Learning. ALL RIGHTS RESERVED. Pancreas Fish-shaped organ located behind the stomach Produces pancreatic juices to digest food Produces insulin which is secreted into the blood stream; regulates burning of carbohydrates to convert glucose to energy Copyright © 2004 by Thomson Delmar Learning. ALL RIGHTS RESERVED.

Diseases and Abnormal Conditions Appendicitis Cholecystitis Cirrhosis Constipation Diarrhea Diverticulitis Gastroenteritis Copyright © 2004 by Thomson Delmar Learning. ALL RIGHTS RESERVED.

Diseases and Abnormal Conditions (continued) Hemorrhoids Hepatitis Hernia or rupture Pancreatitis Peritonitis Ulcer Ulcerative colitis Copyright © 2004 by Thomson Delmar Learning. ALL RIGHTS RESERVED.