1. Digestive tract Department of Histology and Embryology

2. Digestive System tract: Digestive tract: oral cavity, esophagus, stomach, small and large intestines, rectum, and anus. glands: Digestive glands: small gland large gland

3. 1 ． Mechanical processing 2 ． Secretion 3 ． Digestion 4 ． Absorption 5 ． Elimination 1 ． Mechanical processing 2 ． Secretion 3 ． Digestion 4 ． Absorption 5 ． Elimination Slide 14.3 Digestive System Function

4. General structure of the digestive tract Submucosa 2. Submucosa Muscularis 3. Muscularis Adventitia 4. Adventitia Mucosa 1. Mucosa

5. General structure 1. Mucosa: highly variable (1) epithelium: highly variable contains connective tissue that (2) lamina propria: contains connective tissue that is rich capillaries and lymphatic is rich capillaries and lymphatic tissues tissues a thin layer smooth muscle (3) muscularis mucosa: a thin layer smooth muscle fibers fibers 2. Submucosa : dense connective tissue, glands 3. Muscularis: smooth muscle fibers 4. Adventitia: fibrosa or serosa

7. mucosa ： epithelium ： nonkeratinized stratified squamous epithelium lamina propria ： connective tissue muscularis mucosa ： smooth muscle fibers submucosa ： loose connective tissue esophageal gland muscularis ： The upper one third ： Skeletal muscle The upper one third ： Skeletal muscle The middle third ： Skeletal muscle and Smooth muscle The middle third ： Skeletal muscle and Smooth muscle The distal third ： Smooth muscle The distal third ： Smooth muscle Fibrosa Adventitia: Fibrosa Esophagus

12. Stomach Function Function : Food storage * Food storage Absorption * Absorption : water, salt and alcohol and so on Digestion * Digestion

14. Stomach Mucosa Lamina propria: Submucosa Muscularis Adventitia: Adventitia: serosa Epithelium: gastric gland Muscularis mucosae: Smooth muscle Simple columnar epithelium surface mucous cell

15. Surface mucous cell Surface mucous cell secrete a continuous mucous layer that prevents the proteinase solutions in the stomach.

16. 1 ． cardiac gland 2 ． pyloric gland 3 ． fundic gland The neck, the body and the base （ 1 ） parietal cell （ 2 ） chief cell （ 3 ） neck mucous cell （ 4 ） neuroendocrine cell （ 5 ） stem cell Gastric gland

18. Parietal cell （ oxyntic cell ） Secrete HCl and intrinsic factor

19. Chief cell （ zymogenic cell ） Secrete pepsinogen

20. Mucous neck cell  Present between parietal cells Secrete mucous

21. Fundic gland

22. Small intestine Functions: Digestion: Absorption: Endocrine:

23. The structure that increase the absorptive surface area of small intestine plicae circulares intestinal villi microvilli.

25. The Wall of the Small Intestine

26. mucosa epithelium lamina propria small intestinal gland muscularis mucosa Submucosa Muscularis fibrosa 、 serosa Small intestine ： Small intestine ： duodenum, jejunum, ileum intestinal villus plicae circulare

27. Plicae circulares

28. Intestinal villi

29. Central lacteal Capillary

30. Types of cells in intestinal mucosal epithelium Absorptive cells Goblet cells Endocrine cells

31. Small intestinal gland

32. Absorptive cells Goblet cells Paneth cells Endocrine cells Stem cells

33. Absorptive cells Tall columnar LM: Striated border EM: Microvilli Functions: Digestion and absorption Secrete enterokinase

34. Goblet cells Interspersed between the absorptive cells Goblet cell secrete mucin

36. Paneth cells At the base of the small intestinal gland Secrete defensin At the base of the small intestinal gland Secrete defensin

39. Duodenal gland Duodenum

41. Jejunum

42. Ileum

43. Large instestine Difference from small intestine as follows: No plicae circulares and villi More goblet cells No Paneth cells. Difference from small intestine as follows: No plicae circulares and villi More goblet cells No Paneth cells.

44. Large instestine

45. Appendix