Term
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Definition
| drains the digestive tract, pancreas, and spleen; provides approx. 70% of the total hepatic blood flow |
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Definition
| provides 30% of hepatic blood flow (oxygen, primary nutrients) |
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Definition
| the traditional anatomic subunit of the liver |
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Definition
| the functional subunit of the liver when the liver is viewed as a bile-secreting gland |
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Definition
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Definition
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Definition
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Definition
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Term
| Portal area (portal triad) |
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Definition
| contains bile ducts, portal vein, hepatic artery, nerves and lymphatics in fibrous stroma; also contains oval cells (hepatic stem cells); outlined by limiting plate |
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Term
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Definition
| the hepatic cells immediately surrounding the portal triad |
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Term
| Portal vein -> sinusoids -> central vein -> interlobular vein -> hepatic vein -> vena cava |
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Definition
| direction of blood flow in the liver |
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Term
| Centrilobular hepatocytes -> bile canaliculi -> canals of Hering -> bile ductules of portal tracts -> bile duct -> gall bladder |
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Definition
| direction of bile flow in the liver |
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Definition
| macrophages attached on the luminal surface of sinusoidal endothelial cells; clear particulates such as bacteria, endotoxin, and other substances from sinusoidal blood; a source of a variety of inflammatory mediators |
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Definition
| LGLs (large granular lymphocytes) with NK activity that adhere to the sinusoidal endothelium; participate in innate immune defense targeting infected cells in the sinusoidal blood |
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Term
| Hepatic stellate cells (Ito cells, fat-storing cells) |
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Definition
| vitamin A storing cells located within the space of Disse; once activated, these cells transform into myofibroblasts, proliferate, and synthesize collagen and other ECM components; the principle source of hepatic fibrosis during hepatic injury |
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Term
| Smooth endoplasmic reticulum |
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Definition
| responsible for synthesis of cholesterol and bile acids; generation and utilization of glycogen; and metabolism of various substances in preparation for their excretion (bile pigments, xenobiotics, ingested substances, and steroids). also contains mixed-function oxidase system (NADPH, cytochrome reductase, cytochrome P450, etc.) |
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Term
| Rough endoplasmic reticulum |
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Definition
| responsible for production of plasma proteins such as albumin and fibrinogen, lipoproteins, and a variety of alpha and beta globulins, and also all clotting factors except factor VIII |
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Definition
| responsible for energy production by oxidative phosphorylation and beta oxidation of fatty acids |
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Definition
| contain fenestrated endothelial cells, Kupffer cells, and pit cells |
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Term
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Definition
| loss of adequate hepatic function as a consequence of acute or chronic hepatic damage (all hepatic functions are not usually lost at the same time) |
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Term
Disturbances of bile flow (cholestasis) with resultant HYPERBILIRUBINEMIA (icterus)
HEPATIC ENCEPHALOPATHY
Metabolic disturbances - HYPOPROTEINEMIA, HYPERAMMONEMIA and possibly hypoglycemia and acidosis
Hemostatic, vascular and hemodynamic alterations - BLEEDING TENDENCIES (hemorrhagic diathesis), ACQUIRED PORTOSYSTEMIC SHUNT, and ASCITES
Cutaneous manifestations - SUPERFICIAL NECROLYTIC DERMATITIS in dogs, PHOTOSENSITIZATION in herbivores |
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Definition
| potential consequences of hepatic dysfunction and failure |
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Term
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Definition
| pigment produced from breakdown of hemoglobin (and to a lesser extent myoglobin and hepatic cytochromes) |
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Term
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Definition
| a yellow discoloration of tissues produced by increased concentrations of conjugated or unconjugated bilirubin in the blood (hyperbilirubinemia) |
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Term
Prehepatic - intravascular (or extravascular) hemolysis
Hepatic - severe hepatic disease
Posthepatic - biliary obstruction |
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Definition
| causes of hyperbilirubinemia |
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Term
| Severe intravascular hemolysis |
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Definition
| common cause of icterus in ruminants |
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Term
| Acute hepatic dysfunction or deprivation of feed for several days |
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Definition
| common cause of icterus in horses |
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Term
| Hemolysis, hepatic dysfunction, or cholestasis |
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Definition
| common cause of icterus in carnivores |
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Term
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Definition
| Neurologic manifestations (depression, behavioral changes, mania, convulsions) from abnormal neurotransmission in the CNS, caused by specific neurotoxic metabolites (thought to be due to hyperammonemia) |
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Term
Portosystemic shunt
Severe liver damage or rarely urea cycle enzyme deficiency |
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Definition
| two mechanisms by which toxins (such as ammonia) can enter the systemic circulation |
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Term
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Definition
| an inflammation of the skin (usually unpigmented) due to the action of UV light on photodynamic agents deposited in the skin |
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Term
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Definition
| photodynamic pigment produced from ingested plant chlorophyll by GI microflora in herbivores, absorbed from the intestines, and excreted in bile; failure of its excretion by severely damaged liver cells or biliary obstruction results in the accumulation of the pigment in the skin (cause of hepatogenous/secondary photosensitization) |
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Term
Congenital cysts (capsular or biliary)
Hepatic displacement (lobe torsion)
Tension lipidosis (accompanied by telangiecstasia)
Capsular fibrosis
Postmortem autolysis (due to Clostridial proliferation) |
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Definition
| Developmental anomalies and incidental findings |
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Definition
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Term
prehepatic (obstructive thrombosis and narrowing of the portal vein)
Hepatic (increased resistance to blood flow within the sinusoids)
Posthepatic (increased resistance to venous outflow) |
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Definition
| causes of portal hypertension |
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Term
Acquired PSS shunt
Ascites |
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Definition
| consequences of portal hypertension |
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Term
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Definition
| Hepatomegaly with enhanced lobular pattern, liver deep red in color, consistency and texture nearly normal |
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Term
| Chronic passive congestion |
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Definition
| Accentuated lobular pattern with fibrosis and greenish brown hue |
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Term
| Hepatic lipidosis (fatty liver) |
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Definition
| occurs when the rate of triglyceride accumulation within hepatocytes exceeds either their rate of metabolic degradation or release as lipoproteins |
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Term
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Definition
| bovine fatty liver syndrome |
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Term
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Definition
| feline fatty liver syndrome |
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Term
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Definition
| hepatic lipidosis in ponies (esp. Shetland) and miniature horses |
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Term
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Definition
| disease in sheep and goats caused by cobalt/vitamin B12 deficiency |
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Term
| Random (multifocal) degeneration and necrosis |
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Definition
| multifocal aggregates of necrotic hepatocytes scattered randomly throughout the liver with no predictable location within lobules; typical of many infectious agents, such as viruses, bacterial septicemia, and parasitic migrations |
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Term
| EHV-1, salmonellosis, Tyzzer's disease, tularemia |
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Definition
| causes of random necrosis |
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Term
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Definition
| individual and small groups of hepatocytes isolated by fine fibrous septa and small groups of inflammatory cells; occurs in immune-mediated chronic hepatitis characterized by chronic inflammation of the periportal area |
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Term
| Centrilobular (periacinar) degeneration and necrosis |
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Definition
| common pattern of hepatic necrosis resulting from: hypoxia due to anemia or passive congestion, toxicity, or infectious diseases such as ICH and Rift Valley Fever |
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Term
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Definition
| form of necrosis that involves a wedge around the central vein because only the periphery of one acinus is affected; seen as an early manifestation of hepatic hypoxia and precedes centrilobular necrosis |
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Term
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Definition
| least common pattern of hepatic injury; reported causes include aflatoxicosis in horses and pigs, cyanobacteriosis in cattle, and hexachlorophene in cats |
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Term
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Definition
| uncommon pattern of hepatocellular injury that may occur following exposure to toxins such as phosphorus and allyl alcohol that do not require metabolism by MFOs to cause injury |
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Term
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Definition
| refers to necrosis of an entire hepatic lobule or contiguous lobules, not necessarily the entire liver; all hepatocytes within affected lobules are necrotic |
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Term
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Definition
| caused by vitamin E/selenium deficiency; best known cause of massive necrosis |
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Term
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Definition
| refers to a pattern characterized by connection of areas of necrosis between different lobules |
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Term
| Central to central, portal to portal, central to portal |
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Definition
| types of bridging necrosis |
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Term
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Definition
| inflammation of the liver parenchyma |
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Term
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Definition
| inflammation of the biliary ducts, either intrahepatic or extrahepatic |
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Term
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Definition
| involvement of periportal hepatic parenchyma by extension of inflammation from the biliary ducts |
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Term
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Definition
| inflammation that surrounds, but does not encroach on, the biliary ducts |
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Term
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Definition
| accumulation of inflammatory cells within the portal areas |
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Definition
| inflammation of the gall bladder |
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Term
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Definition
| most common cause of hepatic abscesses in ruminants |
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Term
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Definition
| cause of fibrinous cholecystitis in cattle |
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Term
| Clostridium haemolyticum proliferation in areas of necrosis usually caused by Fasciola hepatica migration |
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Definition
| cause of bacillary hemoglobinuria |
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Term
| Infectious necrotic hepatitis (black disease) |
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Definition
| Most common in sheep and cattle; somewhat analogous to bacillary hemoglobinuria but caused by C. novyi |
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Term
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Definition
| an abnormally large hepatocyte that is the result of antimitotic effects of pyrrolizidine alkaloids, which prevent cell division but not DNA synthesis as the hepatocyte attempts to divide to replace necrotic cells |
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Term
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Definition
| the most common and most potent aflatoxin; also a carcinogen |
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Term
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Definition
| pattern of necrosis caused by acetominophen toxicity in cats |
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Term
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Definition
| cats are deficient in the enzyme... |
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Term
| ALT (alanine aminotransferase) |
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Definition
| cytoplasmic enzyme found in the liver only |
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Term
| SDH (sorbitol dehydrogenase) |
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Definition
| cytoplasmic enzyme used in large animals instead of ALT |
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Term
| AST (Aspartate aminotransferase) |
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Definition
| cytoplasmic and mitochondrial enzyme found in the liver as well as muscle, myocardium, and brain |
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Term
| ALP (Alkaline phosphatase) |
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Definition
| associated with or attached to cell membranes of the biliary tract, also found in bone, placenta, kidney and intestine, not necessarily specific to liver |
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Term
| GGT (gamma-glutamyl transpeptidase) |
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Definition
| associated with cell membrane, produced by the bile ducts and other cells including kidney and prostate. Most measurable is of liver origin |
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Term
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Definition
| synthesized by hepatocytes from cholesterol and are the major solids in bile |
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Term
| Regeneration, fibrosis, biliary hyperplasia |
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Definition
| common responses of the liver to injury |
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Term
| Capillarization of sinusoids |
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Definition
| loss of fenestrations in endothelium (occurs along with perisinusoidal fibrosis and a loss of microvilli of hepatocytes) |
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Term
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Definition
| fibrosis centered around the bile ducts in the portal area that occurs in response to inflammation of the portal triads due to cholangiohepatitis, pericholangitis,or biliary obstruction |
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Term
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Definition
| type of fibrosis caused by long-standing right-sided heart failure or chronic toxic injury |
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Term
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Definition
| type of fibrosis caused by chronic inflammatory lesions or some toxins that affect the periportal hepatocytes |
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Term
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Definition
| in severe massive necrosis all parenchymal cells of a number of adjacent lobules are lost, and the residual reticulin network collapses and condenses so that surviving portal areas are approximated to produce broad, irregular bands of scar tissue. This form of fibrosis is due to condensation of preexisting stroma, plus a variable amount of fibroplasia and scarification |
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Term
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Definition
| fibrosis that results from the prolonged or repeated injury affecting all regions of the lobule throughout the liver |
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Term
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Definition
| the fibrosis that links portal to portal, and portal to central veins. May intersect the classical lobules to produce pseudolobulation |
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Term
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Definition
| nonspecific response to various insults to the liver and bile drainage obstruction; can occur independent of changes in the parenchyma or triads |
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Term
| Cirrhosis/end-stage liver |
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Definition
| chronic liver disease characterized by parenchymal regeneration, fibrosis, and often bile duct hyperplasia |
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Term
| Idiopathic chronic liver disease in dogs |
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Definition
| an ill-defined liver disease of dogs characterized by nodular regeneration combined with atrophy and eventual liver failure; thought to be caused by aflatoxins or valvular endocardiosis |
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Term
| Canine chronic (active) hepatitis |
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Definition
| cause undetermined but believed to be immune-mediated; grossly characterized by a small liver often with an accentuated lobular pattern and architectural distortion ranging from a coarsely nodular texture to an end-stage liver; microscopically characterized by portal and periportal mononuclear cell inflammation, intrahepatic cholestasis, and portal fibrosis that may extend into adjacent perioportal areas |
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