Presentation on theme: "Histology for Pathology Gastrointestinal System and Exocrine Pancreas"— Presentation transcript:
1Histology for Pathology Gastrointestinal System and Exocrine Pancreas Theresa Kristopaitis, MDAssociate ProfessorDirector of Mechanisms of Human DiseaseKelli A. Hutchens, MD, FCAPAssistant ProfessorAssistant Director of Mechanisms of Human DiseaseLoyola Stritch School of MedicineWelcome to basic histology of the skin
2ObjectivesOn H&E stained sections, identify the four general layers of the digestive tract organs (esophagus, stomach, small bowel, colon): Mucosa; submucosa; muscularis externa, and adventitia/serosaOn H&E stained sections identify the following components of the mucosa: epithelium, lamina propria, muscularis mucosaDescribe the components of the submucosal layer of the digestive organsExplain the location of Meissner plexus vs Auerbach plexus and describe the function of eachName the type of epithelium comprising the mucosa of the esophagus, stomach, small bowel, appendix, colon and anal canal.Identify submucosal glands in the esophagus and describe their function.Describe the composition of the esophagogastric junctionName the four parts of the stomach.Identify gastric pits and explain their function.On high power H&E stained sections distinguish parietal cells from chief cells. List the substances secreted by each of the cells.
3ObjectivesIdentify the following key components of the small intestine:Duodenum: villi, Brunner glandsJejunum: villi, goblet cellsIleum: villi, goblet cells, Peyer patchesDefine Crypts (or Glands) of Lieberkuhn.Contrast vili vs plicae circularesOn H&E stained sections distinguish colon from small intestine.Define taenia coli. In H&E stained sections of pancreas distinguish the endocrine components of the pancreas from the exocrine components. In H&E stained sections of pancreas identify pancreatic acinar cells vs ducts.
4Oral CavityInner surface of the lips, cheeks, soft palate, surface of tongue, and floor of the mouthNonkeratinized stratified squamous epitheliumLamina propriaSubmucosaGingiva and hard palateKeratinized stratified squamous epitheliumTongue: specialized mucosa with papillae
5Digestive Tract Comprised of hallow organs Esophagus Stomach Small intestineLarge intestineHistologic organization:Mucosa:Epithelium, lamina propria, muscularis mucosaSubmucosa:connective tissue, vessels, and Meissners plexuses, some times mucous glandsMuscularis externa: 2-3 layers of smooth muscle (plus skeletal muscle in esophagus), myenteric (Auerbach) plexus in between muscle layersSerosa and adventitia: Outermost layer of loose connective tissue and blood vessels. Call serosa if covered my mesothelium; adventitia otherwise
6Esophagus Mucosa: non-keratinizing stratified squamous Submucosa: contains mucous glandsIncreased mucous glands at lower esophagus (GE junction) to protect esophagus from gastric juicesMuscularis externa: inner circular and outer longitudinalContains skeletal muscle fibers
9StomachAnatomically and histologically divided into cardia, fundus body, and pylorusCardia: first section; separate from esophagus by cardiac sphincter. Glands contain mucus-secreting cells, stem cells, enterendocrine, and occasional parietal cellsFundus and body: largest portion. Fundic glands contain parietal cells and chief cells with some stem cells, mucous cells and enteroendocrine cellsPyloric region: lower end that connects to duodenum; ends at pyloric sphincter. Glands primarily mucus-secreting cells and two special endocrine cells: gastrin-secreting (G cells) and somatostatin-secreting cells (D-cells)
10Mucosa of the StomachColumnar EpitheliumGastric Pit
12Small IntestineMajor site for absorption of nutrients and its mucosa is made for this!Villi and microvilliGlands (crypts) of Lieberkuhn in lamina propria that open into the mucosa at the base of villi.Paneth cells with pink granules at the base of the crypts secrete lysozymes, tumor necrosis factor-alpha, and defensins.Submucosa with Meissner plexusThree sectionsDuodenum: Brunner glands (mucus secreting)Jejunum: long villi and increased goblet cells – no Brunner glands or Peyer patchesIleum: Short villi, many goblet cells, and lymphatic nodules in the submucosa called Peyer patches
18Large Intestine Major site of absorption of water and salts Mucosa: No villi, gland of Lieberkuhn with many goblet cells and no paneth cells.Submucosa: no glandsMuscularis externa: Inner circular muscle plus outer longitudinal muscle with myenteric (Auerbach) plexus between.Outer longitudinal muscle creates three narrow bands called tenia coli.Four anatomic sectionsCecum :AppendixColonRectum and anal canal
24Exocrine PancreasMany serous secretory cells (pancreatic acinar cells) form acinar structures.Cytoplasm contains zymogen granulesSecretions carried by main duct to join bile duct at the ampulla in the duodenum
25Main pancreatic duct and surrounding acini Main DuctPancreatic Acini