Chapter 12: The Digestive System

1. Chapter 12: The Digestive System

2. Chapter Objectives • Function of the digestive system. • Digestive tract, functions of each part. • Accessory organs and their role in digestion. • Roots pertaining to the digestive system. • Major disorders of the digestive system. • Medical terms used in reference to the digestive system. • Abbreviations used in referring to the gastrointestinal system.

3. Key TermNormal Structure and Function

4. Key TermsNormal Structure and Function (cont’d)

5. Key TermsNormal Structure and Function (cont’d)

6. Key TermsNormal Structure and Function (cont’d)

7. Key TermsNormal Structure and Function (cont’d)

8. Key TermsDisorders

9. Key TermsDisorders (cont’d)

10. Key TermsDisorders (cont’d)

11. Key TermsDisorders (cont’d)

12. Key TermsDisorders (cont’d)

13. Key TermsDisorders (cont’d)

14. Key TermsDiagnosis and Treatment

15. Key TermsDiagnosis and Treatment (cont’d)

16. Supplementary termsNormal Structure and Function

17. Supplementary TermsNormal Structure and Function (cont’d)

18. Supplementary TermsDisorders

19. Supplementary TermsDisorders (cont’d)

20. Supplementary TermsDisorders (cont’d)

21. Supplementary TermsDisorders (cont’d)

22. Supplementary TermsDiagnosis and Treatment

23. Supplementary TermsDiagnosis and Treatment (cont’d)

24. Supplementary TermsDrugs

25. Supplementary TermsDrugs (cont’d)

26. Abbreviations

27. Abbreviations (cont’d)

28. Digestion • Prepares food for cellular intake • Nutrients must be small enough to be absorbed • Nutrients broken down by mechanical and chemical means • Occurs in digestive tract • Food moved by peristalsis

29. Digestive System

30. The Mouth to the Stomach • Digestion begins in mouth • Mastication breaks up food • Tongue, lips, cheek, and palate break up food and mix in saliva • Moistened food passed: • Into pharynx → through esophagus →into stomach • Churning of stomach further breaks down food by: • Mixing with enzyme pepsin and HCl

31. The Mouth

32. Roots for the Mouth

33. Roots for the Mouth (cont’d)

34. Roots for the Digestive Tract(Except for the Mouth)

35. Roots for the Digestive Tract(Except for the Mouth)

36. The Small Intestine • Partially digested food passes through pylorus into duodenum • Digestion completed after passing through other parts of small intestine (jejunum and ileum) • Digested nutrients absorbed into circulation • Aided by villi

37. The Large Intestine • Undigested food, water, digestive juices • Begins with cecum • Colon twists and turns: • Ascending colon • Transverse colon • Descending colon • Water reabsorbed, feces formed • Waste material passes into sigmoid colon • Waste stored in rectum; eliminated through anus

38. Accessory Organs • Salivary glands • Secretes enzyme that begins digestion of starch • Liver • Secretes bile to break down fats • Gallbladder • Bile stored here until needed • Pancreas • Produces mixture of digestive enzymes

39. Accessory Organs

40. Roots for the Accessory Organs

41. Clinical Aspects of the Digestive System • Infection • Can be caused by variety of organisms • Ulcers • Lesion of skin or mucous membrane • Marked by inflammation or tissue damage • Can be diagnosed by: • Endoscopy • Barium study (Radiography with contrast medium)

42. Cancer • Colon and rectum most likely affected area • Risk factors: • Diet low in fiber, high in fat • Heredity • Chronic inflammation of colon (colitis) • Polyps often become cancerous • Symptom: bleeding into intestine

43. Cancer (cont’d) • Internal observations performed with endoscopes • Treatment may require surgical removal of portion of GI tract • May create a stoma for waste elimination • Surgery is called –ostomy, with root named for involved organ (e.g. colostomy)

44. Obstructions • Hernia • Protrusion of organ through abnormal opening • Pyloric stenosis • Opening between stomach and small intestine too narrow • Intussusception • Slipping of part of intestine into part below

45. Obstructions (cont’d) • Volvulus • Intestinal twisting • Ileus • Intestinal obstruction caused by lack of peristalsis • Hemorrhoids • Varicose veins in the rectum

46. Gastroesophageal Reflux Disease • Reflux of gastric juices caused by weakness at gastroesophageal junction • Heartburn likely to occur after meals, when lying down, with hiatal hernia, and pregnancy • Treatment: • Weight loss • Elevate head • Avoidance of irritating foods • Drugs • Surgery

47. Inflammatory Intestinal Disease • Crohn disease • Chronic inflammation of intestinal wall segments, usually ileum • May causes, pain, diarrhea, abscess, formation of fistula • Ulcerative colitis • Continuous inflammation of colon lining, usually rectum

48. Inflammatory Intestinal Disease (cont’d) • Celiac disease • Inability to absorb gluten • Diverticulitis • Many small pouches in wall of intestine • Attributed to diet low in fiber • If pouches collect waste and bacteria, leads to diverticulitis • Treated with diet improvement, stool softeners, drugs to reduce motility

49. Hepatitis • Inflammation of the liver • More than six types of viral infections • Hepatitis A • Spread by fecal-oral contamination • Hepatitis B • Spread by blood and other body fluids • Hepatitis C • Spread through blood or close contact to infected person

50. Hepatitis (cont’d) • Hepatitis D • Highly pathogenic, only affects those with Hepatitis B • Hepatitis E • Spread by contaminated food and water • Hepatitis G • Spread through contact with blood of infected person • Vaccines available for Hepatitis A and B