1. 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.

2. 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.

3. 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.

4. 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.

5. 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.

6. 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.

7. 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.

8. 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.

9. 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.

10. 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.

11. 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.

12. 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.

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

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