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44 Cards in this Set
- Front
- Back
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What is are the endocrine functions of the pancreas?
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Islets of Langerhans secrete insulin, glucagon, somatostatin, etc.
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What are the exocrine functions of the pancreas?
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Acinar cells: digestive enzymes
Centroacinar cells: bicarbonate-rich alkaline fluids Ducts: main and accessory ducts |
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What are the endocrine-like functions of the liver?
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Hepatocytes: albumin, fibrinogen, thrombin, etc.
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What are the exocrine functions of the liver?
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Hepatocytes: bile (secretory IgA, bilirubin glucouronide)
Ducts: bile canaliculi, cystic duct and common bile duct |
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Why are there sometimes two pancreatic ducts and where do they open?
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the pancreas forms when a dorsal and ventral portion fuse. The main duct opens into the greater duodenal papilla. If there is an accessory duct, it opens into the lesser duodenal papilla.
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What are some histological characteristics of Islets of Langerhans?
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stain lighter than surrounding pancreatic tissue
numerous blood vessels |
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What is the difference between secretory granules in alpha and beta cells?
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alpha cells - halo-like appearance
beta cells - granule contents are shriveled and plate-like |
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What are centroacinar cells?
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clear cells that mark the beginning of the intercalated duct in the pancreas
release bicarbonate into the lumen of the duct |
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Why aren't there striated ducts in the pancreas?
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there is no need to modify the secretory contents
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How do the following hormones affect exocrine pancreatic function?
CCK Secretin Pancreatic Polypeptide VIP GIP |
CCK - stimulates exocytosis in acinar cell
Secretin - secretion of H2O and electrolytes PP - opposes action of CCK VIP - stimulates H2O and electrolyte secretion GIP - postprandial stimulation of insulin release |
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What are some distinguishing features of hepatocytes histologically?
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hexagonal lobules in animals
glycogen granules lots of endoplasmic reticulum (rough and smooth) |
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What is the sequence of venous drainage in the liver?
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Terminal hepatic vein (central vein) -> sublobular vein -> collecting vein -> hepatic vein -> inferior vena cava
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What are the components of a portal triad?
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bile duct
hepatic artery portal vein |
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What type of cells line bile ducts?
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cholangiocytes - cuboidal shape
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What is the Space of Disse?
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space between sinusoid endothelium and hepatocyte
hepatocytes have microvilli in the Space of Disse to make effective contact with blood |
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What are Kupffer cells?
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a type of macrophage
phagocytic cells in liver sinusoids |
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What is a Fat Storing Cell of Ito?
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a.k.a. Stellate Cells of Ito
present in the Space of Disse cells with lipid granules in cytoplasm store Vitamin A in lipid droplets important in pathogenesis of liver - can transform into cells making Type I and III Collagen |
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What type of collagen is present in the Space of Disse?
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Type III
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What happens in cirrhosis?
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Ito cells start producing too much collagen (Type I) in the Space of Disse - blood cannot pass through
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What is the sequence of drainage of bile?
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Bile canaliculi -> Canal of Hering -> Interlobular bile duct
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What forms the membrane of a bile canaliculus?
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Membranes of adjacent hepatocytes, sealed by tight junctions
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How does Secretory IgA get to the liver?
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synthesized by plasma cells in the lamina propria of the gut
carried in the lymph to the thoracic duct, then to the liver taken up by hepatocytes as secretory IgA and secreted into the bile canaliculi secretory component is cleaved and antibody is released into the bile for transport to the intestinal lumen |
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What is the function of the gallbladder?
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storage, concentration, and secretion of bile
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What are the three classifications of liver lobules?
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classic lobule
portal lobule liver acinus of Rappaport |
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What is a classic lobule?
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liver loblule whose organization is based on the microscopic appearance of liver in animals
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What is a portal lobule?
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liver lobule based on bile flow
all bile prduced in a single portal lobule flows into one bile duct triangular with central veins making up the corners and a bile duct (portal triad) in the center |
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What is a liver acinus of Rappaport?
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liver lobule based on blood flow through the liver
spans between two portal triads and is elliptical in shape hepatic artery and portal vein as its core |
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What are the three types of convolution of the small intestine?
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Plicae -> Villi -> Microvilli
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What kind of tissue forms the core of plicae?
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lamina propria
muscularis mucosa submucosa |
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What is the function of plicae?
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slow movement of chyme
increase surface area |
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What kind of tissue forms the core of villi?
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lamina propria
lymph ducts |
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Where is the glycocalyx?
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on the surface of microvilli
form the unstirred layer |
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What is another name for the submucosal plexus?
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Meissner's plexus
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What functions are controlled by the submucosal plexus?
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contraction of muscularis mucosae
submucosal vascular tone secretory activity of mucosal epithelium |
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What is another name for the myenteric plexus?
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Auerbach's plexus
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What functions are controlled by the myenteric plexus?
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contraction of muscularis externa:
segmentation and peristalsis |
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What is the main function of enterocytes in the small intestine?
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absorption and secretion of enterokinase
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What are Paneth cells?
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exocrine cells located at the base of crypts in the small intestine
secrete lysozyme and alpha-defensins have antibacterial activity |
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What types of cells are located in the crypt region of the small intestine?
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Paneth cells
stem cells enteroendocrine cells |
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How do crypts contribute cells to microvilli?
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each crypt contributes cells to a small stripe on multiple villi
cells turn over every 3-4 days |
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What is a distinguishing feature of the duodenum?
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Brunner's submucosal glands:
secrete alkaline mucous to neutralize stomach acid |
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What are some features of Gut-Associated Lymphoid Tissue (GALT)?
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plasma cells, macrophages, lymphocytes located in lamina propria and submucosa
intraepithelial lymphocytes lymph nodules - usually in lamina propria, sometimes extending into submucosa Peyer's patches: large aggregates of nodules covered by M cells, specialized for uptake and presentation of antigen |
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What type of mucosa lines the surface of the appendix?
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colonic
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What distinguishes the recto-anal junction?
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transition from columnar to stratified squamous epithelium
internal and external sphincters - smooth and skeletal muscle sebacous glands in anal canal muscularis mucosa breaks up at recto-anal junction |
