Histology lab 7: Mar. 1–2, 2005

Digestive System (continued) II & III—Gastrointestinal Tract, Liver & Pancreas

collection slide # label
description

Stomach

sections from cardiac (ring around entrance of esophagus) or fundus (bulge above), body (below fundus), and pyloric regions (gatekeeper: entry to intestine): rugae (temporary folds) but no villi! surface mucous epithelium dips into gastric pits (foveolae) at isthmus of glands; mucosa: mucous cells (mucocytes), lamina propria, muscularis mucosae (inner circular, outer longitudinal = strands between glands and pits); neck of gland: neck mucous cells, mitotic figures = stem (regenerative) cells; base of gland: enteroendocrinocytes (known as amine precursor uptake and decarboxylation [APUD] cells or diffuse neuroendocrine system [DNES] cells); submucosa, mucous or gut associated lymphoid tissue (MALT or GALT); submucosal (Meissner's) plexus; muscularis externa (oblique, circular, longitudinal; myenteric (Auerbach's) plexus; serosa
Dig. Sys 4508 Stomach composite: sec cardiac/fundic: length gastric pits equal to or less than that of glands; pits broad; cardiac glands simple and branched tubular, may be coiled basally, dominated by mucous cells with occasional parietal (oxyntic) cells in upper half of gland; esophageal glands may run over into cardiac portion of stomach;
body (also called fundic): branches open into shallow, narrow gastric pits (shorter than glands); gastric (also called fundic) glands: mucous neck cells (between parietal cells),  parietal (fried egg [negative image of canaliculli], secrete hydrochloric acid, gastric intrinsic factor [in human beings]) in outer portion, and chief (zymogenic: secrete pepsinogen, renin, lipase) cells in lower portion, enteroendocrinocytes (APUD: secrete serotonin) in base; MALT
pyloric: length gastric pits greater than that of glands; pits broad branched, coiled tubular pyloric glands of mucous cells (secrete mucus and lysozyme), parietal cells rare, no chief cells; enteroendocrinocytes (gastric secreting G cells and somatostatin secreting D cells); MALT; pyloric sphincter

Small Intestine

plicae circulares (permanent folds involving mucosa and submucosa); villi (projections of mucosa): absorptive epithelium with striated (brush) border, glycocalyx and terminal bars slough off tip of villi, goblet cells, lamina propria with lacteals (lymphatic capillaries), capillaries, gut-associated lymphoid tissue (GALT: macrophages, lymphocytes, plasma cells, mast cells), muscularis mucosa: longitudinal outer, circular inner, strands run into villi; submucosa, submucosal (Meissner's) plexus (parasympathetic ganglia); muscularis externa (inner circular, outer longitudinal), myenteric (Auerbach's) plexus; serosa (adventitia); intestinal glands (crypts of Lieberkühn) open into intervillar space: intestinal epitheliocytes, endocrinocytes (APUD cells), basal exocrinocytes (Paneth cells [difficult to identify] secrete lysozyme), mitotic figures = stem cells; serosa (mesothelium) or adventitia (fused to body wall)
Dig. Sys 4526 Duodenum: c.s. large, leaf-like (foliate) villi; moderate number goblet cells; (submucosal) duodenal glands (Brunner's glands);
Dig. Sys
4593
Bile duct mammal: c.s. (same as 4526 except entry bile duct through adventitia of duodenum);  hepatopancreatic ampulla (ampulla of Vater) and sphincter of hepatopancreatic ampulla (of Oddi)
Dig. Sys 4530 Jejunum: c.s. plicae circulares (folds) most developed; large, finger-like villi; increased number goblet cells
Dig. Sys 4534 Ileum: c.s. short, finger-like villi; greatest number goblet cells;  aggregated lymphatic follicles or nodules (Peyer's patches), M (microfold) cells

Large Intestine
Dig. Sys 4542 or 4546 Colon; H&E: c.s. no pits or villi; abundant goblet cells; absorptive cells; glands: enteroendocrinocytes; gut-associated lymphoid tissue (GALT: macrophages, lymphocytes, plasma cells, mast cells), muscularis mucosa (circular inner, longitudinal outer); submucosa, submucosal (Meissner's) plexus (parasympathetic ganglia); muscularis externa (inner circular, outer longitudinal); taniae coli (thickened bands of longitudinal muscle) separate haustra coli (sacculations), myenteric (Auerbach's) plexus and parasympathetic ganglia; serosa or adventitia
Dig. Sys 4558 Recto-anal junction: l.s. abrupt change in type epithelium: simple columnar with goblet cells; stratified squamous of keratinizing type; large perianal glands; adventitia; external sphincter (skeletal); internal sphincter (smooth)
Dig. Sys 6787 Appendix human: c.s. lymphatic follicles or nodules in submucosa (germinal centers indistinct)
Liver, Gall Bladder and Pancreas
Dig. Sys 4566 Liver Pig: sec septa (stroma) delineate classic lobules; portal area (spaces); triad: hepatic artery (arteriole), portal vein, bile duct (generally lymph vessel as well); terminal plate = peribiliary area = limiting hepatocytes; parenchyma: hepatocytes (look for differences between perilobular and centrolobular cells, e.g., binuclear centrolobular hepatocytes) surrounded by bile canaliculi in plates (trabeculae), radiate from central vein (drain into sublobular vein and ultimately hepatic vein); sinusoids (incomplete, fenestrated endothelium) or discontinuous capillaries; bile ductules, cholangioles; serosa (Glisson's capsule)
Dig. Sys 4582 Phagocytosis: sec hepatic fixed macrophages (Kupffer's cells) with ingested ink particles in subendothelial space (space of Disse)
Dig. Sys 4590 Gall bladder: c.s. tall, columnar epithelium; primary bile duct; lamina propria; muscularis externa; serosa; common bile duct
Dig. Sys 4600 Pancreas: sec exocrine: serous acini: apical secretory (zymogen) granules and basal basophilia; vesicular nuclei; no pericytes (myoepithelial cells); centroacinar cells and intercalated ducts (difficult to distinguish except by absence of secretory granules); interlobular ducts with increasing amounts of connective tissue and stratified cuboidal epithelium.
endocrine (pancreatic islets = islets of Langerhans): polarized endocrinocytes; capillaries
note lamellated (Pacinian) corpuscle in some sections



Last Updated: Nov. 22, 2004
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