1. BIO 241 HISTOLOGY REVIEW Digestive System Dr. Tim Ballard Department of Biology and Marine Biology

2. Basic histological plan of the GI tract

3. Esophagus Arrow = epithelium of trachea M = mucosa SB = submucosa ME = muscularis externa A = adventitia

4. Esophagus Arrow = epithelium ME = muscularis externa Arrowheads = Blood vessels in the submucosa

5. Esophagus Arrow = duct of mucous secreting gland in the submucosa mucous gland stratified squamous epithelium

6. Esophagus muscularis externa inner circular outer longitudinal adventitia submucosa

7. Stomach

8. Fundic Stomach Arrowhead = muscularis mucosae Arrow = muscularis externa

9. Arrowhead = neck mucous cells Typical gastric gland parietal cells chief cells

10. Arrow = muscularis mucosae ME = muscularis externa Stomach wall parietal cells chief cells submucosa

11. Arrow = gastric glands Arrowheads = lymphocytes Pyloric stomach

12. Curved Arrow = villus Arrow = Brunners gland Arrowhead = lymphatic tissue Duodenum muscularis externa intestinal gland

13. V = villi S = submucosa PC = plica circularis M = mucularis mucosa arrowheads = intestinal glands Ileum

14. Ileum Arrow = Peyers patches Arrowhead = mesentery villus

15. Arrow = smooth muscle of taenia coli Colon mucosa no villi submucosa muscularis

16. Colon goblet cells simple columnar cells

17. Liver Arrowhead = capsule Arrows = interstitial c.t. Curved arrow = central vein lobule portal triad

18. Liver – portal triad A = Hepatic artery B = Portal vein C = bile duct simple cuboidal epithelium

19. Liver – hepatocytes and sinusoids A = central vein B = Portal tract Look for sinusoids as the spaces between cords of hepatocytes

20. Liver – bile canaliculi Arrowhead = endothelium of central vein sinusoid Look for canaliculi between adjacent rows of hepatocytes

21. Pancreas -- lobules Arrow = Islets of Langerhans Arrowhead = septa lobule

22. Pancreas -- acinus interlobular duct connective tissue acini