Lect 36 & 37- Digestive Glands and Liver Flashcards
what does the delicate CT of the pancreas contain
blood vessels, lymphatics, nerves, and excretory ducts
what is the main excretory duct in the pancreas
duct of wirsung
what is the small accessory duct in the pancreas
duct of santorini
what are interlobular ducts of the pancreas lined with
simple columnar epithelium and goblet cells
what are intercalated ducts of the pancreas lined with and what cells are in there
lined with low cuboidal cells: cells with receptors for secretin and that secrete water and bicarbonate ion
what do plasma cells in the parotid gland of the pancreas secrete
immunoglobulin A
what do the centroacinar cells of the pancreas form
form a truncated epithelium within the lumen of acini that is continuous with the epithelium of the intercalated duct (unique to pancreas)
what is the release of digestive enzymes from serous acinar cells stimulated by
CCK
what are bicarbonate-rich alkaline fluids released by and in response to what
released by ductal epithelial cells in response to secretin
how are synthesis and secretion of digestive enzymes in pancreas controlled
by peptides secreted by duodenal enteroendocrine cells
what is the secretion of bicarbonate ions in the pancreas regulated by
secretin
describe A cells (alpha cells) of the islets of langerhans
have fine cytoplasmic granules and are presumed to form glucagon
describe B-Cells (beta cells) of the islets of langerhans
have coarse cytoplasmic granules; they are more numerous than alpha cells and produce insulin
describe D-cells (delta cells) of the islets of langerhans
secrete somatostatin, which helps to control levels of insulin and glucagon
what does the space of disse do
separates hepatic cells from endothelial cells
active in transfer between blood and parenchyma
what is then space of mall continuous with
space of disse
what does the space of mall drain into
lymphatics
describe classic hepatic lobules
central venule is in the center of the lobule
portal triads are at the angles
describe portal hepatic lobules
three central venues of adjacent lobules forms a triangle
portions of the bile canaliculi of the 3 lobules drains into the same bile duct
describe the liver acinus hepatic lobules
includes 3 zones defined by hepatic tissue receiving blood form a branch of the hepatic artery conducting blood to opposite central veins
metabolic gradient extends from hepatic triad to central vein
what happens in zone one of the hepatic lobule
hepatocytes actively synthesize glycogen and plasma protein. oxygen concentration in sinusoidal blood is high
what happens in zone 3 (central venous drainage) of hepatic lobules
it is the region where oxygen concentration is poorest. it has a role in detoxification. hepatocytes are susceptible to damage caused by hypoxia
where is the portal triad found
at angles (corners) of classic lobule
what are the components of the portal triad
branch of hepatic artery (arteriole)
branch of portal vein (venule)
bile duct (ductule)
what does the limiting plate of the hepatocytes surround
portal space
what types of fibers are found in the space of disse
1, 3, and 4
define canal of hering
terminal point of the network of bile canalicular trenches found on the hepatocyte surfaces. located at the periphery of the hepatic lobule and connects with the bile ductules in the portal space after perforating the limiting membrane
describe the basolateral domain of a hepatocyte
microvilli
faces space of disse
involved in absorption of blood-borne substances and secretion of plasma proteins
what does the apical domain of hepatocytes border
bile canaliculus
what type of epithelium is in the canal of hering
squamous to cuboidal simple epithelium
what is the lining of the hepatic sinusoids like
fenestrated with endothelial cells
discontinuous basal lamina
where are perisinusoidal cells located and what do they do
located in space of desse
store vitamin A
produce collagen fibers and extracellular matrix components
what happens to perisinusoidal cells during cirrhosis
they transform into myofibroblasts and become the main collagen type 1 producing cells (stimulated by cytokines form hepatocytes, kupffer cells and lymphocytes)
what does the sub endothelial space of disse contain
microvilli of basolateral domain of hepatocytes
type 1, 3, and 4 collagens
interstitial fluid that drains into the space of mall that drains into lymphatics
what are characteristics of kupffer cells
phagocytic cell
derived from monocytes
lines hepatic sinusoids
what does the bile canaliculus receive
bile from hepatocytes
what does the canal of herring do
receives bile from canaliculus
carriers bile to bile ductule
what does blood coagulation depend on that is produced in the hepatocyte
fibrinogen, prothrombin, factor VIII
what do complement proteins do (ER in hepatocytes)
synthesized by hepatocytes, participate in destruction of pathogens
what do the mucosal folds of the neck of the gallbladder form
the spiral valve of heister
what is the epithelium in the mucosa of the wall of the gallbladder
epithelium is tall columnar with a striated border
describe the lamina propria of the mucosa of the wall of the gallbladder
has extensive vascular plexuses and may contain a few smooth muscle cells
small diverticula of the mucosa which extend into the muscular and perimuscular layers and may indicate pathological change
rotikansky-aschoff sinuses
describe the serosa of the wall of the gall bladder
has a broad perimuscular CT coat, rich in blood and lymphatic vessels and elastic fibers
what does the gallbladder release bile in response to
cholecystokinin stimulation (produced by enteroendocrine cells in the duodenum) and neural stimuli together with relate of the sphincter of Oddi
define sphincter of oddi
muscular ring surrounding the opening of the bile duct in the wall of the duodenum
what is the mucosa of the ducts lined with (liver/gallbladder?)
columnar epithelium with goblet cells
where is alcohol oxidized to acetaldehyde (ethanol met)
in the cytoplasm
where is acetaldehyde converted to acetate (ethanol met)
in mitochondria
what is catalase
major protein of peroxisome that decomposes H2O2 into H2O. it is a tetramer of apocatalase molecules assembled within peroxisome
what does TNF-alpha do during chronic liver diseases
causes a slow down and arrest of the flow of nine in nine ducts
what is transforming growth factor beta secreted by
kupffer cells and hepatocytes
what releases interleukin-6
kupffer cells
what are the bile components
cholic and chenodeoxycholic acid (synthesized by hepatocytes)
deoxycholic acid and lithocholic acid (converted by bacteria)
water and electrolytes
cholesterol and phospholipids
pigments and organic molecules
what is the major pigment in bile
bilirubin
where is conjugated bilirubin secreted into
intestine
what is conjugated bilirubin in the intestine converted by and into
by bacterial action into urobilinogen
where do bile salts emulsify dietary lipids
small intestine
