2. Digestive System

3. Basic Divisions – Digestive tract – Accessory organs: various exocrine glands

4. Digestive Processes – Ingestion – Mechanical Processing – Motility PeristalsisPeristalsis

5. Digestive Processes – Ingestion – Mechanical Processing – Motility Peristalsis

6. Digestive Processes – Ingestion – Mechanical Processing – Motility Peristalsis Segmentation movements

7. Digestive Processes, continued – Chemical digestion – Secretion – Absorption – Excretion and defecation

8. Non-Digestive Functions of Digestive Tract – Immunity – Storage of iron

9. Layers of the digestive tract – Mucosa Epithelium Lamina propria (areolar CT) Muscularis mucosae

10. Layers of the digestive tract, continued – Submucosa includes the submucosal plexus

12. Layers of the digestive tract, continued – Muscularis externa: responsible for peristalsis and segmentation movements longitudinal layer circular layer myenteric plexus

13. Layers of the digestive tract, continued – Serosa (the visceral peritoneum is an example) Simple squamous epithelium Areolar CT  Within peritoneal cavity only

14. Layers of the digestive tract, continued – Adventitia Dense irregular CT  Oral cavity, pharynx, esophagus, rectum

15. The Peritoneum – Parietal p. – Visceral p.

16. The mesenteries – Mesentery proper – Mesocolon – Greater omentum – Lesser omentum – Falciform ligament

21. Accessory structures of the oral (buccal) cavity – Teeth: will cover in lab – Tongue: read textbook – Salivary glands buccal glands lingual glands

23. Oral (buccal) cavity – Salivary Glands buccal glands lingual glands major salivary glands – parotid

25. Oral (buccal) cavity – Salivary Glands buccal glands lingual glands major salivary glands – parotid – sublingual – submandibular

29. – Structure of salivary glands glandular epithelium merocrine cells

30. – Structure of salivary glands glandular epithelium merocrine cells compound tubulo-acinar

33. – Functions of saliva lubrication for swallowing, speaking re-mineralizes tooth enamel buffer antibodies (IgA) dissolves food molecules some chemical digestion

34. Pharynx – To be discussed with the respiratory system

35. Esophagus – Structural features muscular tube about 25 cm long posterior to larynx, trachea pierces diaphragm through esophageal hiatus

39. 2 Esophogeal sphincters: – upper esophageal sphincter – lower esophageal sphincter

41. Histology highlights – mucosa – submucosa: lots of mucous glands – muscularis externa – adventitia (no serosa)

44. Gastroesophageal Reflux

45. Stomach – Location

46. Stomach – Location: from epigastric and umbilical region

47. Stomach – Location: from epigastric and umbilical region to left hypochondriac regions

48. Gross Structural Features – cardiac region – fundus – body – pylorus – pyloric sphincter

49. Stomach motility videoStomach motility video

50. Stomach Histology – mucosa

51. Stomach Histology – mucosa: location of gastric glands

52. Stomach Histology – mucosa: location of gastric glands

53. Stomach Histology – mucosa: location of gastric glands gastric gland cells – mucous cells – parietal cells – chief cells – endocrine cells

54. Stomach Histology, continued – muscularis: three layers

55. Stomach Functions – food reservoir – formation of chyme – some chemical digestion – regulation of chyme entry into S.I. – intrinsic factor production – some absorption

56. Digestive System, review Basic Divisions – Digestive tract – Accessory organs: various exocrine glands

57. Pancreas – Location Umbilical region

59. Pancreas – Location Umbilical region Retroperitoneal

61. Pancreas Gross Structure – Head – Body – Tail

62. Pancreas Gross Structure – Head – Body – Tail – Ducts pancreatic accessory

63. – pancreas histology mostly glandular epithelium – exocrine pancreas – endocrine pancreas

64. – exocrine pancreas functions – sodium bicarbonate – digestive enzymes

66. – endocrine pancreas structure: thousands of islets of Langerhans

68. – endocrine pancreas function: hormone secretion – glucagon – insulin – somatostatin

69. Liver –Location: epigastric and right hypochondriac regions

70. Liver –Location: epigastric and right hypochondriac regions

72. Liver –Gross structure: 2 major lobes separated by the falciform ligament

74. Liver Blood Supply – Hepatic portal vein – Hepatic arteries

77. Liver Histology – Functional unit:

78. Liver Histology – Functional unit: liver lobule

81. Liver Histology – Functional unit: liver lobule

82. Liver Histology – Functional unit: liver lobule – Liver cells

83. Liver Histology – Functional unit: liver lobule – Liver cells hepatocytes Kupffer cells

85. – Each liver lobule supplied by branches of: hepatic arteries hepatic portal veins

87. – Liver Functions Maintains blood glucose levels Cholesterol synthesis HDL and LDL synthesis Plasma protein synthesis

88. – Liver Functions, continued Hormone and drug removal Phagocytosis Vitamin storage Iron storage Bilirubin excretion

91. – Liver Functions, continued Hormone and drug removal Phagocytosis Vitamin storage Iron storage Bilirubin excretion

92. – Liver Functions, continued Hormone and drug removal Phagocytosis Vitamin storage Iron storage Bilirubin excretion Bile salt secretion

94. Gall Bladder – Location: right lumbar region

96. Liver Blood Supply – Hepatic portal vein – Hepatic arteries

97. Gross Structural Features of Gall Bladder – Muscular sac – Mucosa folded into rugae – Bile enters and leaves through cystic duct

98. Gall Bladder Function – Stores and concentrates bile – Contracts during meals to force bile into SI

101. Biliary Pathway

102. Biliary Pathway: “plumbing” which drains bile

107. Small Intestine – 1 inch diameter – 10-20 ft. in length duodenum (10 in) jejunum (3-6 ft.) ileum (6-12 ft)

108. Features of SI mucosa – Plica circularis

109. Features of SI mucosa – Plica circularis

110. Features of SI mucosa –Plica circularis –Villi

111. Features of SI mucosa –Plica circularis –Villi

112. Features of SI mucosa –Plica circularis –Villi

113. Features of SI mucosa –Plica circularis –Villi –Microvilli

114. Features of SI mucosa –Plica circularis –Villi –Microvilli

115. Features of SI mucosa, cont’d –Epithelial cell types: absorptive cells Goblet cells Endocrine cells Paneth cells

117. Features of SI mucosa, cont’d –MALT in lamina propria

118. Features of SI mucosa, cont’d –MALT in lamina propria

119. Features of SI mucosa, cont’d –MALT in lamina propria –Intestinal glands (“crypts”)

121. Features of SI submucosa –Submucosal glands in duodenum

122. Motility of SI –Segmentation movements –Peristalsis

123. Functions of small intestine – Completion of chemical digestion “brush-border” enzymes required – Absorption – Endocrine control of some digestive processes

124. Summary movie

125. Large Intestine

127. Large Intestine (large bowel)

128. –2.5 inches in diameter

129. 5-6 feet long –Cecum –Colon Ascending Transverse Descending Sigmoid –Rectum –Anal canal

136. Features of LI mucosa – no villi – numerous intestinal glands – goblet and absorptive cells in epithelium – MALT in lamina propria

137. Structural Features of cecum and colon – Taeniae coli – Haustra – Epiploic appendages

139. Other Structural Features – Vermiform appendix

142. Other Structural Features – Vermiform appendix

143. Other Structural Features – Vermiform appendix – Ileocecal valve

145. Other Structural Features – Vermiform appendix – Ileocecal valve

146. Other Structural Features – Vermiform appendix – Ileocecal valve – Stretch receptors in rectum initiate defecation reflex

147. Other Structural Features – Vermiform appendix – Ileocecal valve – Stretch receptors in rectum initiate defecation reflex – Anal sphincters of anal canal

149. Motility of Large Intestine – From cecum to transverse colon: peristalsis – From transverse colon to rectum: mass movements

150. Functions of Large Intestine – Water and electrolyte absorption – Feces formation – Defecation

151. Large Intestinal Bacteria – Coat surface of mucosa – Examples: E. coli – Keep out pathogenic bacteria

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