Microscopic anatomy of liver disease Flashcards
The image below shows normal liver microanatomy. What do each of the numbers labelled relate to?
1 - hepatocytes
2 - bile canaliculi
3 - bile duct
4 - branch of hepatic vein
5 - portal triad
6 - hepatic artery
7 - sinusoids
8 - central vein
What are the sinusoids of the liver?
- vascular spaces between hepatic plates
- blood flows from portal triad to central vein
What are the bile cannaliculi of the liver?
- sit between hepatocyes as these produce bile
- bile oves from central vein to portal triad
What are hepatic nodules?
- hexagon shapes of liver organisation
- central vein is in the middle
Acinar zones 1,2,3 are zones within the hepatic lodules. What is the relevence of the acinar zones?
- receiving blood progressively poorer in oxygen and nutrients close to central vein
- zone 3 will recieve blood that has been extracted of O2 and nutrients from zones 1 and 2
Acinar zones 1,2,3 are zones within the hepatic lodules. The acinar zones receive blood progressively poorer in oxygen and nutrients close to central vein. For example, zone 3 will recieve blood that has been extracted of O2 and nutrients from zones 1 and 2. Out of the 3 zones which is likley to suffer from ischemia and become damaged?
- zone 3
In the liver histology section image below, what do the colour arrows depict?
- red = hepatic artery
- green = bile duct
- blue = portal bein
In the liver histology section image below, what do the darker spots around the sinusoids depict?
- inflammatory cells
What is the space of Disse?
- a location in the liver between a hepatocyte and a sinusoid
- contains blood plasma
- can only been seen in pathophysiology
The sinusoidals of the liver are lined by a specific type or endothelial cell, what is this cell and what is the importance of this?
- fenestrated (like a sink hole with little holes)
- allows transfer of nutrients and plasma between hepatocytes and blood vessels
What are the immune cells of the liver?
- kupffer cells (macrophages)
Stellate cells of the liver, sit in the space of disse and are important for storage. What do they store?
- vitamin A
Hepatocytes contain a fine granuler eosinophilic cytoplasm. What colour does this stain on H&E staining?
- protein stain pink
- nucleus stains blue
Do hepatocytes contain glycogen?
- yes and can be stained for
- important for energy and blood glucose of liver
The image below is H&E stain of hepatocytes. What do the numbers 1, 2 and 3 denote?
1 - sinusoids
2 - nuclei of hepaticytes
3 - kupffer cells
In addition to storing and metabolising vitamin A, what else do stellate cells do?
- play a leading role in fibrogenesis
- cells transform into myofibroblasts that can lay down collagen
- reticulin fibers lay down collagen III, fibrous collagen can cause liver dysfunction
What is the white space in the image below of hepatocytes?
- central vein
In the image of the bilary tree below, what do the numbers 1-8 denote?
1 - right hepatic duct
2 - cystic duct
3 - gall bladder
4 - ampulla
5 - pancreatic duct
6 - bile duct
7 - common hepatic duct
8 - left hepatic duct
What cells line the bilary tree intrahepatically?
- cholangiocytes
- intrahepatic has small ducts and large ducts
- small = portal tracts (columnar) and surface epithelium (cuboidal)
- large ducts = surface epithelium surrounded by fibrous duct wall (columnar)
What cells line the bilary tree extrahepatically?
- cholangiocytes
- all columnar surface epithelium surrounded by fibrous duct wall
- contain a Muscle layer but not well defined until distal common bile duct (lower 1/3 of extrahepatic bile duct)
In ALD and NAFLD where does fat accumulate?
- in the cytoplasm of hepatocytes
The fat that gathers in the cytoplasm of hepatocytes in ALD and NAFLD can be classed as Macro and Microvesicular steatosis, what does this mean?
- macrovesicular steatosis = fat vacuoles larger than the nucleus, displace nucleus
- microvesicular steatosis = fat vacuoles smaller than the nucleus and mostly a foamy appearance with central nucleus
To confirm a diagnosis of steatosis, what other changes are needed to be classified as steatohepatitis?
- hepatocellular ballooning degeneration.
- mallory-denk bodies (intermediate cytoskeleton)
- necroinflammation
- fibrosis
What causes a hepatocyte to balloon?
- hepatocytes are filled with fat
- cells are unable to regulate the cell size
- cytoskeleton, specifically intermediate filaments then clump together
When hepatocytes balloon, why do they appear clear?
- cytoskeleton is not able to maintain cells and so collapses
In normal liver tissue there should be no gaps between hepatocytes, except for at the sinusoidals. However, in the image below of H&E staining there are empty spaces. What does this image show, identified by the arrows?
- spaces where inflammatory cells have destroyed hepatocytes
- neutrophils are present
- this is called necroinflammation
The liver should have no collagen in the parenchyme, howeverm in inflammation, what is parenchyme tissue replaced with?
- collagen and fibrosis
- called chicken wire fibrosis
- liver cells are yellow and fibrosis is red
In NADLD, where can be reveressed?
- liver fibrosis
In NADLD, once a patient has fibrosis and cirrhosis, what is the risk of increased?
- hepatocarcinoma
- liver cancer
What does cirrhosis refer to in liver disease?
- yellow nodules form on the liver
- end stage diffuse scarring process
- nodularity can be macronodular or micronodular (depends on the size)
