1. Gastrointestinal (GI) System
Chapter 14

2. Digestion overview
Food enters the mouth, travels down the esophagus into the stomach, followed by the small intestine, large intestine, and finally the anus, where it leaves the body.

3. Functions of Gastrointestinal Tract
Digestion
Food taken in and digested mechanically by the mouth and chemically by digestive enzymes in the body
Absorption
Nutrients from food (sugar, fatty acids, and amino acids) enter the bloodstream via the walls of the small intestine and go to cells in the body
Cells burn/breakdown (catabolize) nutrients, in presence of oxygen, to release energy
Cells use amino acids to build (anabolize) large protein molecules for growth and development
Elimination
Solid waste materials that cannot be absorbed are concentrated (feces) in the large intestine and pass out of the body

4. Anatomy of Gastrointestinal Tract
Oral cavity: cheeks, lips, hard palate, soft palate, rugae, uvula, tongue, tonsils, gums, teeth, salivary glands
Mastication (chewing) and deglutition (swallowing) break down and move food to stomach via the esophagus
Salivary glands produce saliva that contains digestive enzymes that help break down food
Pharynx: also called throat
Is a muscular tube or passageway for food to pass through the esophagus (and air to the trachea)
When you wall, a flap called the epiglottis covers the trachea so food does not enter the windpipe

5. Anatomy of Gastrointestinal Tract

6. Anatomy of Gastrointestinal Tract

7. Anatomy of Gastrointestinal Tract
Esophagus:
a muscular tube that connects the pharynx to the stomach
Involuntary rhythmic muscular contractions called parastalsis move the food down to the stomach
Stomach:
Contains enzymes and acid to prepare food for the intestine
Sphincters control the openings into (cardiac sphincter) and out of (pyloric sphincter) the stomach.
Digestion takes about 1-4 hours

8. Anatomy of Gastrointestinal Tract

9. Anatomy of Gastrointestinal Tract
Small intestine:
Extends about 20 ft.
Contains villi (microscopic projections) that absorb nutrients into the bloodstream
3 parts: duodenum, jejunum, ileum
Large intestine:
Extends about 5 ft, but 2x as wide as the small intestine
Receives the waste products of digestion
Absorbs most of the water from the waste and expels the waste in the form of feces

10. Anatomy of Gastrointestinal Tract

11. Anatomy of Gastrointestinal Tract
Liver:
Produces bile
Maintains normal glucose levels
Removes poisons from the body
Gall bladder:
Stores bile
Pancreas:
Secretes enzymes to digest fat
Secretes insulin that carries glucose into the cells to be used for energy

12. Anatomy of Gastrointestinal Tract

13. Anatomy of Gastrointestinal Tract

14. Clinical Divisions of Gastrointestinal Tract

15. Diagnoses assoc. with GI Tract
Gastroesophageal reflux disease (GERD)
Heart burn
Backflow of stomach contents into the esophagus which causes a burning sensation in the esophagus and chest
Often due to abnormal function of cardiac sphincter which prevents it from completely closing

16. Diagnoses assoc. with GI Tract
Peptic ulcer disease (PUD)
Sore in the stomach lining, duodenum, or other part of the GI tract exposed to gastric juices.
Commonly caused by a bacterial infection

17. Diagnoses assoc. with GI Tract
Hepatitis
Hepatitis A
Infectious inflammation of liver caused by hepatitis A virus (HAV), usually transmitted orally through fecal contamination of food or water
Hepatitis B
Infectious inflammation of liver cause by hepatitis B virus (HBV) that is transmitted sexually or by exposure to contaminated blood or body fluids
Hepatitis C
Inflammation of liver caused by hepatitis C virus (HCV) transmitted by exposure to infected blood (rarely contracted sexually)

18. Diagnostic Tests and Procedures assoc. with GI Tract
esophagogastroduodenoscopy (EGD)
AKA upper GI endoscopy
Used to examine the lining of the esophagus, stomach, and duodenum with a flexible endoscope

19. Diagnostic Tests and Procedures assoc. with GI Tract
endoscopic retrograde cholangiopancreatography (ERCP)
Endoscopic procedure including x-ray fluoroscopy to examine the ducts of the liver, gallbladder, and pancreas

20. Diagnostic Tests and Procedures assoc. with GI Tract
nasogastric (NG)
A tube inserted through the nose and into the stomach for a variety of purposes
Feeding
Obtain specimens for analysis