Liver And Gall Bladder Flashcards
What are the livers two sources of blood?
Portal vein and hepatic artery
What is the space of Disse?
What does it contain?
Fluid filled space between endothelial cells and hepatocytes (space is continuous with plasma). Interface for interaction between liver and blood
Contains Stellate cells
What are 2 functions of stellate cells?
Store vit A
Can synthesize collagen and thus can cause hepatic fibrosis
What are the two models describing the arrangement of the hepatic parenchyma?
Classical subunit is hepatic lobule
Classical subunit is hepatic acinus
In the hepatic lobule model, what is the centre and what is the periphery? What is the shape?
Centre: hepatic venule or central venule
Periphery: portal venule hepatic arteriole bile duct, lymphatics, nerves
Shape: hexagonal
In the hepatic acinus model, what is the centre, what is the periphery, and what is the shape?
Centre: terminal afferent branches of the portal venule and the hepatic arteriole
Periphery: hepatic venules
Shape: diamond shape
What are the 3 zones and which is most and least oxygenated?
Zone 1 = periportal (most oxygenated)
Zone 2 = midlobular
Zone 3 = centrilobular (least oxygenated)
What species is the gall bladder absent in? Where does the common bile duct empty into?
Horse and rat
Duodenum
What are the 5 normal liver functions?
- Bilirubin metabolism
- Bile acid metabolism
- Carbohydrate metabolism
- Lipid metabolism
- Protein synthesis
What type of icterus is caused by an increase in the breakdown of RBCs?
Prehepatic icterus
What is the cause of hepatic jaundice?
Decreased uptake of bilirubin due to liver disease (bilirubin accumulates because the liver is not removing it from the blood)
What is the cause of post-hepatic icterus?
Decrease hepatic excretion of bilirubin with bile (cholestasis)
What is the most common type of icterus in ruminants?
Prehepatic icterus
What species develops physiologic icterus with starvation? Why?
Horses
Bilirubin uptake is energy dependent and is decreased during starvation
What is random distribution of degeneration and necrosis caused by?
Bacteria, viruses, Protozoa
What are the 5 types of zonal distribution of degradation and necrosis?
Centrilobular
Paracentral
Periportal
Midzonal
Bridging necrosis
What are the 2 common causes of centrilobular pattern necrosis?
Toxins requiring metabolic activation
Passive congestion of the liver
Describe the paracentral pattern of necrosis
Involves only a wedge around the central vein (one acinus affected)
What is the term that describes necrosis of an entire hepatic lobule or contagious lobules?
Massive necrosis
What are the two types of cholestasis? What is affected? What causes it?
Intrahepatic cholestasis- affects bile caniliculi or ductules within the liver, caused by liver injury (fibrosis)
Extrahepatic cholestasis- affects extrahepatic bile duct, caused by obstruction due to a mass within or outside of the lumen. Will lead to intrahepatic cholestasis
When will you see regenerative nodules?
Extensive loss of hepatocytes and loss of extracellular matrix scaffold (reticulin)
What are the 2 differentials when you see regeneration nodules (lumps and bumps)?
Neoplasia and granulomatous inflammation
What is happening when a liver is small, firm and pale white and may have a nodular appearance to it?
Fibrosis
What are the 3 processes of end stage liver (cirrhosis)?
Degeneration and necrosis
Regeneration (regenerative nodules)
Fibrosis
What is the definition of hepatic failure?
Loss of adequate hepatic function as a consequence of either acute or chronic hepatic damage
What are the 4 consequences of hepatic failure?
Hepatic encephalopathy
Metabolic abnormalities
Vascular and hemodynamic alterations
Cutaneous manifestations
What is an example of vascular and hemodynamic alteration?
Acquired portosystemic shunt which is an abnormal vascular communication between the portal vein and the systemic circulation
What are the two types of cutaneous manifestations?
Superficial necrolytic dermatitis
Photosensitization secondary to hepatic dysfunction
If there is pale areas in the livers of horses and cattle, what is it and is there a cause for concern?
Tension lipidosis, incidental finding
What are 5 examples of hepatic lipidosis in vet med?
Pregnancy toxaemia
Bovine fatty liver disease
Feline fatty liver syndrome
Hyperlipemia
Endocrine disorders like diabetes and hypothyroidism
What are the 2 causes of glycogen accumulation (steroid hepatopathy)?
Prolonged administration of corticosteroids
Secondary to hyperadtenocorticism
what is an example of circulatory disorders with disturbances of outflow? What is it secondary to?
central passive congestion within the liver, secondary to right-sided heart failure
What are 2 circulatory disorders that are problems with inflow?
anemia and congenital portosystemic shunt
What is only found in acquired shunts and absent in congenital portosystemic shunts?
portal hypertension
What will you see if you have a portosystemic shunt upon necropsy? How do you tell if it is acquired or congenital?
Blue vessels
congenital - in younger, no fibrosis, diffuse liver atrophy
acquired - in older animals, secondary to fibrosis (some sort of injury to the liver), may see ascites
if the liver is normal otherwise but has little red spots in cattle, horses and cats, what is the most likely cause? Is it significant?
Telangiectasis, no incidental finding
what is infarction?
it is necrosis, secondary to lack of blood flow
why are liver infarcts uncommon? What can they happen secondary to?
uncommon due to dual blood supply
can occur secondary to torsion of a liver lobe, or can happen secondary to thrombosis
what is the most common cause of an enlarged, orange and friable liver?
amyloid accumulation
Bedlington terriers have a mutation that causes what?
copper accumulation/toxicity, the mutation decreases excretion of copper
what should you sample of you suspect copper toxicity?
fresh liver, blood sample is okay if you are in a hepatic crisis
what are some gross lesions seen with copper toxicity?
icterus, black kidneys because of hemoglobinuric staining, enlarged spleen because of hemolytic crisis
what are the three portals of entry to the liver?
hematogenous
ascending from intestine through bile ducts
direct penetration
what are the gross features of acute hepatitis?
white spots indicative of necrosis and inflammation
what are the gross features of chronic hepatitis?
fibrosis, nodular regeneration, granulomas, abscesses
what infectious disease causes multifocal hepatic necrosis and fetal abortion or neonatal death?
herpesvirus infections
what is a bacterial disease in foals that affects the cecum or colon and liver causing multifocal hepatic necrosis and possibly colitis and myocarditis?
Tyzzer’s disease, caused by Clostridium piliforme
What 2 bacteria cause liver abscesses in feedlot cattle?
Fusobacterium necrophorum mixed with Trueperella pyogenes causes abscesses formation
are liver abscesses significant in feedlot cattle? When could it be a problem?
Typically an incidental finding that would cause liver condemnation at slaughter, unless the abscesses open into the central vein or vena cava and cause pulmonary embolism or cause central vein thrombosis and occlusion causing hepatic passive congestion and portal hypertension
what can cause liver abscess formation in foals?
Rhodococcus equi
what bacterial disease loves the kidneys, and causes intervascular hemolysis with visible hepatic necrosis, where should you isolate the organism?
Leptospirosis
isolate culture from the kidneys
what are some protozoal diseases that can infect the liver?
toxoplasma and neospora
what are some fungal diseases that can infect the liver?
Aspergillus, blastomyces, coccidioides, and histoplasma
what nematode of pigs causes milk spotted liver?
Ascaris suum
What parasite when in the vena cava in large number can cause DIC, intravascular hemolysis and acute hepatic failure?
Dirofilaria immitis (vena caval syndrome)
What do cestodes do in the liver, what are the adult stages?
Cysticercus cyst (smaller) adult stage Taenia
Hydatid cyst (bigger) adult stage Echinococcus
what trematode inhibits the biliary system of ruminants?
Fasciola hepatica
what trematode migrates through the parenchyma of ruminants?
Fascioloides magna
what trematode inhabits the bile duct of dogs and cats?
Metorchis
what is the most common pattern of acute liver toxicity? Why?
centrilobular necrosis because it is the zone with the lowest oxygen tension and the highest concentration of metabolic enzymes
what are the 6 major mechanisms through which toxicity occur, whats the most common?
- production of injurious metabolites (most common)
- formation of neoantigens
- induction of apoptosis
- injury to cell membranes and activation of proteases
- disruption of bile secretion
- mitochondrial damage
what can be seen histologically with Pyrrolizidine alkaloid toxicity?
megalocytes (big hepatocytes)
If an old dog comes into pathology with raised nodules (not many) on the surface of the liver with no fibrosis, what do you expect it is?
Nodular hyperplasia, not significant, age related
if you see an umbilicated, raised lesion on the liver of a cat, what do you suspect it is?
Chollangiocellular carcinoma
what causes bacillary hemoglobinurea in ruminants? What has a similar pathogenesis? How do you differentiate them?
Clostridium hemolyticum
Infectious necrotic hepatitis (black disease) caused by Clostridium novyi
Black disease, there is no intravascular hemolysis
What causes healthy well doing pigs to drop dead?
Hepatosis dietetica caused by vitamin E or Se deficiency
what causes infectious canine hepatitis?
Canine Adenovirus 1
what does lymphocytic cholangitis cause?
lymphocytic infiltration centered on bile ducts with bile duct hyperplasia and fibrosis
what are common causes of cholecystitis in cattle and dogs?
cattle - Salmonella Dublin
dog - infectious canine hepatitis
what is it called when mucosa is thickened with many surface cysts? is it significant?
Cystic mucinous hyperplasia, incidental finding
