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81 Cards in this Set
- Front
- Back
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four structural layers of the GI tract (in to out) |
mucosa, submucosa, muscularis, serosa
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three layers of mucosa
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specialized epithelial layer, lamina propria, muscularis mucosae
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describe submucosa
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connective tissue with lots of blood vessels, lymphatics, and nerves
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describe muscularis
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smooth muscle, inner circular, outer longitudinal
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describe serosa
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thin connective tissue layer and single layer of squamous epithelium moistened by transudate
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describe esophageal mucosa lining
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stratified squamous epithelium
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describe esophageal muscularis mucosae
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elastic fibers in upper, smooth muscle in lower
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describe esophageal muscularis externa
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upper 1/3: skeletal only, middle 1/3: skeletal and smooth, lower 1/3 smooth only
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describe esophagus outermost latyer
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lacks serosa, has adventitia which blends with thoracic connective tissue
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what is the cardia?
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narrow ring around gastro-esophageal junction
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where are cardiac glands?
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in the cardia
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where are pyloric glands?
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mucosa in distal antrum and pylorus
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where are fundic glands?
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fundus and body of stomach (aka gastric or oxyntic glands)
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what do fundic glands do?
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secrete HCl and pepsinogen
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what are surface mucous cells?
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tall columnar cells in stomach surface epithelium, secrete mucigen
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what are gastric pits?
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funnel shaped invaginations in stomach, lead into gastric glands
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list the 4 cell types in the gastric glands
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mucous neck cells, chief cells, parietal cells, enteroendocrine cells
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describe mucous neck cells
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small cells in transition zone between gastric pit and gastric gland, differentiate and migrate upwards to replace surface mucous cells
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describe chief cell appearance
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large cuboidal cells in the middle to lower portions of gastric gland, large zymogen granules
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describe parietal cell appearance
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largest, pyramidal/oval, in upper and middle portions of gland, intracellular secretory canaliculi on apical surface, lots of mitos
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what is intrinsic factor?
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glycoprotein, binds B12 and helps its absorption, secreted by parietal cells
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describe enteroendocrine cell appearance
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in deeper gastric and pyloric glands
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difference between gastric and intestinal lamina propria
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gastric is very delicate, reticular fibers fibroblasts, few lymphocytes, intestinal is highly cellular with lots of lymphocytes
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describe gastric muscularis externa
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highly developed, 3 layers of muscle
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name the three structures that increase small intestine surface area
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plicae circulares, villi, microvilli
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what are plicae circulares?
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transverse concentric folds of submucosa
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what are villi?
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projections of mucosa, lamina propria core, extend from plicae, covered by absorptive epithelia and goblet cells
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what are microvilli?
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apical brush burder, fingerlike projections of plasma membrane
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two types of epithelial cells on villi surface
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absorptive epithelia and goblet cells
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describe absorptive epithelial cells
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tall columnar cells
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describe goblet cells
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apical mucinogen droplets
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describe villus structure
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beneath epithelium, plexus of fenestrated capillaries, lots of lymphoid cells, then a central lacteal (blind ended lymphatic capillary)
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where are crypts of Lieberkuhn?
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bases of the villi
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describe paneth cell appearance
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lage, pyramidal, apical cytoplasm has lots of eosinophilic granules
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what do paneth cells secrete?
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lysozyme and defensins
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how does lysozyme function?
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digests bacterial cell wall
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how do defensins function?
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small peptides that permeabilize bacterial plasma membranes
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what are peyer's patches
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collections of lymphoid elements in the lamina propria in the ileum
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What do M cells do?
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sampel luminal contents and transfer antigens to peyer's patches
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where is Meissner's Plexus
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submucosa
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where is Auerbach's Plexus
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between the circular and longitudinal layers of the muscularis externa
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What do Brunner's glands do?
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secrete alkaline mucus that neutralizes acid from the stomach
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where are Brunner's glands?
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in the duodenum
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how is large intesting mucosa diff from small intestine mucosa?
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absence of villi, abundant crypts of Lieberkuhn, lots of lymphoid cells in lamina propria
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describe blood flow trends in liver
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flows centripetally, from terminal hepatic arterioles and portal venules to sinusoids to central vein
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describe hepatocyte sinusoid surface
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basal, incomplete basement membrane and microvilli
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what are oval cells?
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pluripotent cells in zone 1, mature into hepatocytes
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what cells line sinusoids?
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sinusoidal epithelial cells
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what is so special about sinusoidal epithelial cells?
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discontinuous fenestrated endothelium, incomplete BM, lots of fenestrae
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what is the space of disse
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area with basement membrane
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what are kupffer cells?
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immobile macrophages in the liver, monocyte derived
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where do you find stellate cells?
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in the space of disse or between hepatocytes
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primary histological feature of stellate cells?
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contains lots of fat droplets (retinol)
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stellate cells play a critical role in the onset of which disease?
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hepatic fibrosis
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which cells store retinol?
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stellate cells
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gross appearance of liver in acute hepatitis?
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swollen, bulging, red/yellow, soft and mushy
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microscopic features of acute hepatitis?
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acidophilic necrosis, balooning degeneration, inflammation, cholestsis, bile duct proliferation
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what color is acidophilic necrosis?
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eosinophilic shrunken hepatocytes
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is ballooning degeneration reversible?
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yes
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where does bile ductular proliferation take place?
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periportal zone
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what are necrotic hepatocytes replaced by?
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macrophages and hemorrhage
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list the 4 clinical phases of hepatitis
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incubation, pre-icteric, icteric, recovery
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microscopic features of chronic hepatitis
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portal tract monos, periportal fibrosis
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inflammation pattern in acute hepatitis
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more lobular
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what is interface hepatitis?
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focal cell necrosis and inflamm changes mostly at edge of portal tracts
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what is disrupted terminal plate?
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chronic inflammatory cells that penetrate into lobule adjacent to portal zone
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where is hepatocyte regeneration seen?
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edge of portal tract
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what is bridging hepatic necrosis?
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parenchymal hepatocyte loss extending across lobules, confluent necrosis
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what are ground glass hepatocytes?
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seen in HBV, hepatocytes stuffed with HBSag, light pink cyto
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histo features of HCV?
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prominent aggregates of lymphos in portal tracts
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microscopic appearance of chronic hepatitis?
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interface, disrupted terminal plate, regeneration, fibrosis/scarring, apoptosis, bridging necrosis, ground glass
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where does steatohepatitis usually occur?
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in central zone near central vein
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where does fibrosis start in steatohepatitis?
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central zone, called centrizonal hepatitis
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what are mallory bodies?
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masses of cytokeratin filaments in cytoplasm of hepatocytes
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in which disease do you get mallory bodies?
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alcoholic steatohepatitis
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Do you get mallory bodies in NASH?
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nope
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microscopic appearance of Cirrhosis?
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fibrosis, architectural distortion, hepatocyte regeneration, mono inflammation, intrahepatic shunts
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what are intrahepatic shunts?
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reorganization of vascular architecture, new shunts which connect inflow with outflow, bypassing lobules
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list the patterns of scarring in cirrhosis
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portal based, centrizonal based
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in which diseases does portal based scarring occur?
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chronic hepatitis, chronic biliary tract disease, PBC, PSC, HH
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in which diseases does centrizonal based scarring occur?
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alcoholic and non-alcoholic steatohepatits, ischemic injury, venous outflow obstruction
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