Chapter 14: The Gastrointestinal (GI) System

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.

Function of the GI tract1. ______________________________________________

Food taken in and digested mechanically by the mouth and chemically by digestive enzymes in the body

2. ______________________________________________ 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

3. ______________________________________________ Solid waste materials that cannot be absorbed are concentrated (feces) in the large

intestine and pass out of the body

Anatomy of the GI tract Oral cavity: cheeks, lips, hard palate, soft palate, rugae, uvula, tongue, tonsils, gums, teeth, salivary

glands ___________________________________________(chewing) and ____________________________________________

(swallowing) break down and move food to stomach via the esophagus

______________________________________________________________ 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 _____________________________________________________ covers the

trachea so food does not enter the windpipe

___________________________________________________ a muscular tube that connects the pharynx to the stomach Involuntary rhythmic muscular contractions called ______________________________________________

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

Small intestine: Extends about 20 ft. Contains villi (microscopic projections) that absorb nutrients into the bloodstream

3 parts: _______________________________________________________________________________________________

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

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

Clinical Divisions of GI tract

Diagnoses assoc. with GI tract

_________________________________________________________________________________________________________________ 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

_______________________________________________________________________________________________________________ Sore in the stomach lining, duodenum, or other part of the GI tract exposed to gastric juices.

Commonly caused by a bacterial infection

Hepatitis Hepatitis A

Infectious inflammation of liver caused by

_________________________________________________________________________ usually transmitted orally through fecal contamination of food or water

Hepatitis B Infectious inflammation of liver cause by

__________________________________________________________________________ that is transmitted sexually or by exposure to contaminated blood or body fluids

Hepatitis C Inflammation of liver caused by

___________________________________________________________________________ transmitted by exposure to infected blood (rarely contracted sexually)

Diagnostic Tests and Procedures

_________________________________________________________________________________________________________________ AKA upper GI endoscopy

Used to examine the lining of the esophagus, stomach, and duodenum with a flexible endoscope

_________________________________________________________________________________________________________________ Endoscopic procedure including x-ray fluoroscopy to examine the ducts of the liver,

gallbladder, and pancreas

___________________________________________________________________ A tube inserted through the nose and into the stomach for a variety of purposes

Feeding Obtain specimens for analysis