1 / 74

Chapter 41

Chapter 41. Digestive System. Digestion and absorption. It is the physical and chemical break down of food Absorption It is the passing of the digested food through the epithelial cells into the blood stream. Digestive system. Gastrointestinal tract. It is the alimentary canal Mouth

nola
Download Presentation

Chapter 41

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chapter 41 Digestive System

  2. Digestion and absorption • It is the physical and chemical break down of food • Absorption • It is the passing of the digested food through the epithelial cells into the blood stream

  3. Digestive system

  4. Gastrointestinal tract • It is the alimentary canal • Mouth • Pharynx • Esophagus • Stomach • Small intestine • Large instestine

  5. Accessory digestive organs • Salivary glands • Gallbladder • Liver • Pancreas • Teeth

  6. General histology of the gastrointestinal tract • It has 4 tunics • Mucosa • Epithelium – simple columnar • Lamina propria – areolar tissue • Muscularis mucosa • Smooth muscle that enables movement of the mucosa

  7. General histology of the gastrointestinal tract • Functions of the mucosa are secretion, absorption, protection • Submucosa • Dense connective tissue • Blood vessels • Lymph nodes and vessels • Submucosal plexus • Functions are nutrition and protection of the mucosa

  8. General histology of the gastrointestinal tract • Muscularis externa • Inner circular layer of smooth muscle • Outer longitudinal layer of smooth muscle • Myenteric plexus • Allows GI movements

  9. General histology of the gastrointestinal tract • Serosa (abdominal organs) • Most outer layer • Mesothelium – areolar tissue • Functions is to reduce friction between GI organs • Adventitia • Coarse fibrous tissue that binds the GI organs to the surrounding tissues. Anchors and protects them

  10. Oral cavity

  11. Macroscopy of the digestive tract • Oral cavity or mouth • Oral cavity • Lips or labia • Superior and inferior labial frenulum • Cheeks • Palate • Soft with uvula • Hard • Palatine raphe

  12. Macroscopy of the digestive tract • Tongue • Mylohyoid muscle • Lingual frenulum • Vestible • Palatine tonsil • Palatoglossal arch • Palatopharyngeal arch

  13. Macroscopy of the digestive tract • Lingual tonsil • Salivary glands • Saliva • Salivary amylase • Pharynx • Nasopharynx • Oropharynx • Laryngopharynx

  14. Macroscopy of the digestive tract • Esophagus • Peristalsis • Gastroesophageal sphincter • Adventitia and not serosa • Stomach • Cardiac region • Fundus • Body

  15. Macroscopy of the digestive tract • Pyloric region • Pyloric sphincter • Greater curvature • Greater omentum • From the greater curvature down to the abdominal organs • Lesser curvature

  16. Macroscopy of the digestive tract • Lesser omentum • From the lesser curvature to the liver • Gastric pit • Gastric rugae • Function of the stomach is to process the food forming the chyme

  17. Histology of the stomach

  18. Histology of the stomach • Mucosa • Gastric glands • Chief or zymogenic cells: • Located on the fundus • Produce pepsinogen

  19. Histology of the stomach • Parietal cells: • Located on the fundus • Produce HCL • Produce intrinsic factor Enteroendocrinecells: • Located on the pyloric region • Release hormones • Submucosa

  20. Histology of the stomach • Muscularis externa • Oblique layer • Circular layer • Longitudinal layer • Gastroesphageal junction (Cardioesophageal) • Stratified squamous epithelium on the esophagus • Simple columnar on the stomach

  21. Small intestine • From the pyloric sphincter to the ileocecal valve • Mesentery Proper • Double layer of peritoneum that attaches the small intestine to the posterior body wall

  22. Small intestine • Plicae • Deep folds of the mucosa and submucosa • They cause the chyme to spiral through the intestine slowing and mixing it • Intestinal crypts of crypts of Lieberkuhn • It is the invaginated area of the mucosa between the villi

  23. Small intestine • Lacteal • It is the lymphatic capillary present in each villus • Function of the small intestine • Nutrients absorption

  24. PART B

  25. Subdivisions of the small intestine

  26. Small intestine • Duodenum • Pancreatic duct • Bile duct • Hepatopancreatic ampulla • Major duodenal papilla • Hepatopancreatic sphincter or sphincter of Oddi • Duodenal glands or Brunner’s glands – located in the submucosal layer

  27. Small intestine • Jejunum • Where the food is most absorbed • Ileum • Ileocecal valve • Peyer’s patches • Aggregation of lymphoid tissue more prominent in the ileum

  28. Small intestine • Superficial structures of the small intestine that increases the absorptive area of the mucosa • Villi • Fingerlike projections of the mucosa

  29. Small intestine • Microvilli or brush border • Projections of the cell membrane of the columnar epithelium • Brush border enzymes • Plicae

  30. Histology of the small intestine • Identify these structures on the slide: • Plica • Cripts • Villi • Brush border • Layers of the intestine

  31. Histology of the small intestine • Duodenum • Submucosa with Brunner’s glands • Jejunum • Longest, leafy villi • Ileum • Submucosa with Peyer’s patches

  32. The large intestine

  33. Large intestine • From the ileocecal valve to the anus • Mesocolon • Attaches the large intestine to the body wall • Cecum • It is the first part • Appendix • A blind tube like structure connected to the cecum

  34. Large intestine • Colon: • Ascending • Right side of the abdominal cavity • Right colic (hepatic) flexure • It is retroperitoneal • Transverse • Cross the abdominal cavity • Left colic (splenic) flexure

  35. Large intestine • Descending • It is retroperitoneal • Sigmoid • S-shaped • Located in the pelvis • Rectum

  36. Large intestine • Anus • External sphincter - skeletal muscle • Voluntary • Internal sphincter – smooth muscle • involuntary

  37. Large intestine - structures • Tenia coli • It is the longitudinal muscle layer of muscularis externa • It is in the shape of a muscle band • Haustra • Pocket like sacs of the large intestine • It is caused by the tenia coli

  38. Large intestine - structures • Epiploic appendages • Fat-filled pouches of visceral peritoneum hanging for the colon’s surface

  39. Large intestine • Functions of the large intestine • Consolidate and propel the fecal matter to the anus • Site for intestinal bacteria to synthesize vitamins B and K • Site for water absorption

  40. Histology of the large intestine • Lumen • Crypts • Layers of the digestive tract • Mucosa with the maximum amount of goblet cells • No villi

  41. Accessory digestive organs • Teeth: • Deciduous (milk teeth) • They appear between 6 month and 2 ½ years of age • They begin to shed at 6 years of age • They are completely shed by the age of 12

  42. Accessory digestive organs • Permanent • They begin to appear at 6 years of age • They last for a lifetime

  43. Types of teeth

  44. Accessory digestive organs • Classification of the teeth • Incisors • Chisel shaped • Shearing action when biting • 4 superiors and 4 inferiors (2 centrals and 2 laterals) • Single-rooted

  45. Accessory digestive organs • Canines • Cone-shaped • It tears the food • 2 superiors and 2 inferiors • Single-rooted

  46. Accessory digestive organs • Premolars • Two cusps • It grinds the food • 4 superiors and 4 inferiors • 2 first premolars • 2 second premolars • Generally single-rooted • 1st premolar may have 2 roots

  47. Accessory digestive organs • Molars • They have broad crowns • Rounded cusps • 6 superiors and 6 inferiors • 2 first molars • 2 second molars • 2 third molars or wisdom teeth • They have 2 roots • They grind food into fine pieces

  48. Accessory digestive organs • Dental formula: • Deciduous • 2,1,0,2 2,1,0,2 • Permanent • 2,1,2,3 2,1,2,3

  49. Accessory digestive organs • Anatomy of the teeth • Crown • Clinical • Anatomical • Enamel • It consists mainly of calcium salts • Gum or gingival • Gingival sulcus and margin

  50. Accessory digestive organs • Neck • Root • Cementum • Periodontal ligament • Dentin • Pulp • Contain blood vessels and nerves • Pulp cavity

More Related