Gastrointestinal (GI) System Chapter 14

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. https://www.youtube.com/watch?v=08VyJOEcDos

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

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

Anatomy of Gastrointestinal Tract

Anatomy of Gastrointestinal Tract

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

Anatomy of Gastrointestinal Tract

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

Anatomy of Gastrointestinal Tract

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

Anatomy of Gastrointestinal Tract

Anatomy of Gastrointestinal Tract https://www.youtube.com/watch?v=NZ4zcrTzUjA

Clinical Divisions of Gastrointestinal Tract

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

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

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)

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

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

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