The Digestive System

1. The Digestive System Medical Terminology

2. Key Terms: GI • Asymptomatic • Defecation • Duodenal bulb • Endoscope • Exocrin • Pepsin • Varices • Sphincter

3. GI Anatomy • Mouth • Pharynx • Esophagus • Stomach • Small intestine • Large intestine • Rectum • Anus

4. Mouth Anatomy • Oral cavity/buccal cavity • Teeth • Enamel, dentin, pulp (nerves & vessels), gingiva • Salivary glands • Begin chemical breakdown of food into nutrients • Bolus (of food) • Chemical processing • Mechanical processing (mastication)

5. Mouth Anatomy • Tongue • Assists mechanical processing of food • Assists swallowing (deglutition) • Has papillae (taste buds) • Sweet, sour, salty, bitter • Hard and soft palates • Hard palate = anterior • Soft palate = posterior

6. Pharynx • Uvula • Inferiormost portion of pharynx • Divides into • The trachea (anteriorly) • The esophagus (posteriorly) • Has the epiglottis • Protective fold of tissue over the trachea • Prevents aspiration

7. Abdominal Structures • Stomach • In LUQ • Allows both chemical & mechanical digestion • Parts: Fundus, Body, Pylorus • Separated by LES (lower esophageal sphincter, or cardiac sphincter) and pyloric sphincter • Has rugae (tissue folds) and glands that make HCl, make bolus into chyme • Has peristalsis to move bolus into duodenum

8. Small Intestine • Approximately 20 + feet in length • Has three parts: • Duodenum • Jejunum • Ileum, ends at the ileocecal valve

9. Digestive Organs • Pancreas • Exocrine part of the gland • Assists in fat digestion • Pancreatic enzymes enter into the duodenum • Liver • Helps to make bile • Also assists in fat digestion • Bile is stored (with cholesterol) in the gall bladder • Bile enters in the duodenum

10. Liver • Bile production (fat digestion) • Synthesis of glycogen from glucose • Maintaining glucose levels • Glucose synthesis from amino acids • Vitamin storage (B12, A,D,E,K,) • Destruction, recycling of RBC’s and bilirubin • Metabolism of drugs & toxins • Protein synthesis • Including clotting factors

11. Pancreas • In upper abdomen, across RUQ & LUQ • Endocrine function: insulin secretion • Exocrine function: digestive enzymes • Trypsin: digests proteins • Amylase: digests CHO • Lipase: digests fats • Through pancreatic duct to duodenum

12. Gall Bladder • Sac-like storage structure, infrahepatic • Stores bile in solution with cholesterol • Bile helps in fat digestion • Stimulus for GB secretion is duodenal or distal stomach bolus of food • Has cystic duct • Merges with hepatic duct to become the CBD (common bile duct) which enters the duodenum

13. Large Intestine • Approximate length is 5 feet • Secretes mucus, absorbs water • Five major parts • Cecum (including appendix) • Ascending colon (to hepatic flexure) • Transverse colon (to splenic flexure) • Descending colon • Sigmoid colon, recum, anus

14. GI Combining Forms • Oro-, stomato- = mouth • Gloss-, linguo- = tongue • Bucco- =cheek • Chielo-, labio- = lip • Dento-, odonto- = teeth • Gingivo- = gums • Sialo- =salivary glands

15. Combining Forms: GI • Entero- = intestinal (small intestine) • Colo-, colono- = large intestine • Procto- = anus, rectum • Cholangio- = biliary vessel • Chole-, cholecysto- = gall bladder • Choledocho- = bile vessel

16. Suffixes: • -emesis = vomit (hematemesis, hyperemesis) • -megaly = enlargement (hepatomegaly) • -orexia = appetite (anorexia) • -pepsia = digestion (dyspepsia) • -phagia = swallowing, eating (polyphagia) • -prandial = meal (post-prandial) • -rrhea = discharge, flow (diarrhea)

17. Pathology: Ulcers • Peptic Ulcer Disease (PUD) • Related to hydrochloric acid and pepsin in gastric secretions • S/S: burning upper abd pain, nausea, may be exacerbated or improved with food intake, supine symptoms • Various degrees: • From GERD (mild) to ulcers in duodenum or stomach • Helicobacter pylori • Risk factors: NSAID’s, caffeine, smoking, Etoh

18. Hernia • Abnormal protrusion of a body cavity wall. • May contain soft tissues, organs, etc. • Abdominal types of hernia: • Inguinal: in groin area, commonest in infancy • Strangulated: tissues inside hernia are ischemic • Umbilical: through umbilicus • Diaphragmatic: from abdomen into chest, may be traumatic or congenital, respiratory symptoms • Hiatal: involves lower esophagus and the stomach, through hiatus in diaphragm • Incarcerated: contents are trapped inside hernia, not ischemic

19. Ulcerative Colitis • Chronic inflammatory disease of large intestine (colon) and rectum • Starts in sigmoid or rectum • Profuse, watery diarrhea with mucus, pus, blood • Mucosal lining involvement only, no intervening normal mucosal tissue • High risk of colon cancer • Treatment is largely surgical

20. Bowel Obstruction • May occur in small or large bowel • Most common etiology: adhesions (scar tissue) from previous surgery or GI disease • Several types of obstruction: • Volvulus: coil of intestine twists on itself • Intussusception: telescoping of bowel into itself • Compression from outside the bowel: adhesions, etc.

21. Hemorrhoids • Varicosities of veins in the anal canal • Internal or external • Nonsurgical treatment usually • Associated with high intraabdominal pressure: • Straining, pregnancy, liver disease (cirrhosis), standing or sitting for long periods.

22. Liver Diseases • Hepatitis = inflammation of liver • Etiology may be viral or chemical, medications • Hepatitis A (infectious hepatitis): from food or drink • Hepatitis B (serum hepatitis): from transfusions and sexual contacts • Cirrhosis = fibrotic scarring of liver • Usually due to chronic damage of some sort • Alcohol is common etiology, also chemicals, heredity • Jaundice (icterus): yellowish color of skin due to excessive bilirubin in serum

23. Diverticulosis • Diverticuli (tiny, blister-like pockets of epithelium) herniate through the intestinal wall. • Most common in sigmoid colon area (LLQ) • May become inflamed, infected, or rupture (diverticulitis) • Treatment is usually antibiotics and pain control, rarely surgical except in cases of large intraabdominal abscesses

24. Oncology: • Stomach Cancer • Rare in US, epithelial cancer • Persistent indigestion, often acid symptoms • Colorectal Cancer • Epithelial layer is source • S/S: changes in bowel habits, blood in feces, weight loss, abdominal pain, sudden obstruction

25. Oncology • Esophageal Cancer • Obstructive symptoms, poor prognosis • Hepatocellular Carcinoma • More common in cases of chronic inflammatory conditions of liver, poor prognosis • Pancreatic Cancer • Difficult to find and resect • Locally invasive, involvement of spinal nerves so often painful, pain radiates posteriorly • Poor prognosis

26. Related Terms • Anorexia • Appendicitis* • Ascites* • Borborygmus • Cachexia • Cholelithiasis* • Crohn’s Disease (regional enteritis) (ileum)*

27. Related Terms • Cirrhosis* • Colic • Deglutition • Dysentery (inflammatory intestinal condition usually caused by bacteria, parasites, bloody diarrhea is hallmark of disease) • Dyspepsia • Dysphagia -common with esophageal diseases

28. Related Terms: • Eructation • Fecalith • Flatus • GERD (gastroesophageal reflux disease)* • Halitosis • Hematemesis • IBS (irritable bowel syndrome): unknown etiology*

29. Related Terms • Malabsorption Syndrome • Oral leukoplakia • Melena • Pancreatitis* • Peristalsis • Pyloric stenosis • Regurgitation • Steatorrhea

30. Diagnostic procedures & tests • Endoscopy • Upper GI (gastroscopy) • Lower GI (colonoscopy) • Liver function tests & hepatitis panel • Stool culture & stool guaiac • Barium enema & swallow • CT, ERCP, Ultrasonography, Biopsy

31. Therapeutic Procedures • Nasogastric intubation/suction (NGT) • Resections and ostomies • Colectomy, colostomy, ileostomy, etc • Various GI anastomoses • Lithotripsy • Polypectomy • pyloromyotomy

32. Pharmacology: • Antacids • Antidiarrheals • Antiemetics • Antispasmodics • Laxatives • Antibiotics • Antiulcer (histamine-2 blockers & proton pump inhibitors)