Histology - Liver, Gall Bladder Flashcards
simple cuboidal epithelium. Located in portal area and collect bile from liver lobules via intrahepatic bile ductules.
interlobular bile ducts
major support for hepatic sinusoids
reticular fibers
liver dysfunction due to venous congestion, usually cardiac dysfunction or other causes of hypoperfusion and hypoxia. Affects hepatocytes near central vein.
centrilobular necrosis
pericytes found in the perisinusoidal space (space of Disse). The major cell type involved in liver fibrosis (scar tissue).
Ito Cells
cholangiocarcinoma
cancer in biliary system
causes simultaneous contraction of smooth muscle of gallbladder and relaxation of smooth muscle of sphincters
cholecystokinin
Will cause necrosis throughout liver lobule
viral hepatitis
a collagenous capsule covering the external surface of the liver. It consists of type III collagen and extends to the stroma of endothelial sinusoids.
Glisson’s capsule
Ito cells lose ability to store lipid and vitamin A. Primary function becomes collagen synthesis.
liver cirrhosis (chronic inflammation)
breakdown product of hemoglobin from dead rbcs
bilirubin - modified in hepatocytes and released in bile for elimination.
migratory macrophages derived from monocytes located within hepatic sinusoids that form a part of the sinusoidal lining. Unique to hepatic sinusoids.
Kupffer cells
a type of sinusoidal blood vessel (with fenestrated, discontinuous endothelium) that serves as a location for the oxygen-rich blood from the hepatic artery and the nutrient-rich blood from the portal vein.
liver sinusoid
Four of six sides. Desmosomes and tight junctions holding cells together, preventing material from moving from one hepatocyte to another.
lateral domains
hepatocytes with lower oxygen tension, and lower nutrient and hormone levels. Increased number of SER, but less mitochondria, for biochemical pathways requiring less ATP (such as glycolysis, cholesterol synthesis, fatty acid synthesis, and drug metabolism)
Perivenous hepatocytes
yellow discoloration of skin due to abnormally high levels of bilirubin in bloodstream. can occur with medical conditions that impair liver function like congestive heart failure.
jaundice
Parenchyma
the functional parts of the liver - hepatocytes
intercalated ducts join to form intralobular ducts, then interlobular ducts, then finally the main or accessory pancreatic ducts
interlobular pancreatic duct - note: cuboidal epithelium becomes columnar epithelium in duct system.
Fenestrated Cpilaries
Pancreas, Small Intestine. Have pores that are spanned by a diaphragm of fibrils and allow small molecules and limited amounts of protein to diffuse.
outside of stroma a space between connectuve tissue stroma and parenchyma of liver (hepatocytes). Fluid in perisinusodal flows to this space and is the origin of the lymph vessels.
periportal space of Mall
veins found at the center of a “classic” hepatic lobule. They receive the blood mixed in the liver sinusoids and return it to circulation via the hepatic vein.
central vein of liver (or central venules)
adventitia of Gallbladder
loose connective tissue attaches to Glisson’s capsule non attached is serosa, portion attached to liver has adventitia.
Cuboid exocrine cells.
Centroacinar cells - pale nucleus, basal membranes have receptors for secretin from duodenum. Located at center of pancreatic acinus. Produce alkaline fluid to keep digestive enzymes inactive until they reach the duodenum.
portal lobule
triangular; centered on a portal triad, bile secretion. 3 central veins in periphery, bile drinas to center, blood to periphery.
classical lobule
hexagonal; central vein central. Six portal areas in periphery, blood drains centrally, bile drains to periphery, separated by septa.
pyramid shaped exocrine cells, release granules of digestive enzymes.
Acinar cells. have receptors for CCK from duodenum apex. Contain secretory granules (zymogen granules) granules are full of digestive enzymes and proenzymes like trypsinogen, chymotrypsinogen, carboxypeptidase, amylase, lipase, nuclease.
70% of islet cells, center of islet, produces insulin
B-Cell
separates sinusoidal lining cells from hepatocytes, intermediary space between blood and hepatocytes.
Perisinusoidal space (or space of Disse). Microvilli of hepatocytes extend into this space, allowing proteins and other plasma components from the sinusoids to be absorbed. Contains Ito Cells, drins into lymph. Can be obliterated in liver disease, leading to decreased uptake by hepatocytes of nutrients and wastes (bilirubin).
concentrattion of bile system
active transport of sodium out of epithelial cells into intercellular space that causes passive aquaporin-mediated movement of water into epithelial cell lamina propria.Sodium and water then taken up by vascular system, leading ot water in lumen to passively move into epithelial cells. Continual flow of water form lumen into cells, to vascular system of laminal propria in wall of gall bladder driven by sodium active transport into intracellular space.
exocrine pancreas
pancreatic acini - tubuloacinar serous glands. 40-50 acinar cells per pancreatic acinus. Basal lamina separates acinar from septa.
derived from vitelline vein. Between plates of hepatocytes, blood draining from portal areas to central vein.
hepatic sinusoids
hepatocytes in portal area (high ox. conc.)that contain an increased number of golgi apparati, RER, and mitochondria for biochemical pathways requiring more ATP (such as protein synthesis, amino acid catabolism, gluconeogenesis, and the urea cycle).
Periportal hepatocytes
20% of islet cells, on periphery, produces glucagon
A-cell
hepatocyte features
Derived from endoderm, quarter are binucleate, most polyploid. Six-sided cubes, 20-30 um in diameter. Two sinusoidal domains, four lateral domains.
the connective, functionally supportive framework derived from mesoderm
stroma, Glisson’s Capsule, septa, reticular fibers
release of bile mechanism
bile is released from GB by enteroendocrine cells during digestion in response to cholecystokinin.
hepatic acinus of Rappaport
oval or diamond-shaped; distributing arteriole is at center of lobule, two central veins and two portal veins are in periphery. zones of oxygenation.
epithelial cells of biliary system
cholangiocytes - beginning with intrahepatic bile ductules, microvilli and long primary cilium.
5% of islet cells, periphery of islet
D-Cell - produce somatostatin
a small division of the liver defined at the histological scale.
hepatic lobule
A space in the lateral domain where there are no junctions that allows an opening (or groove) to form.
Bile Canaliculi - A thin tube that collects bile secreted by hepatocytes. The bile canaliculi merge and form bile ductules, which eventually become common hepatic duct.
connective tissue stroma continuous with Glisson’s capsule that contain blood vessels, bile ducts, nerves, lymph vessels. Separate hepatocytes into liver lobules.
liver septa
