Term
| What are the lobes of the liver? |
|
Definition
-right lateral
-right medial
-quadrate
-left lateral
-left medial
-caudate |
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Term
| Describe the blood supply input to the liver. |
|
Definition
-75% portal vein
-25% hepatic artery |
|
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Term
| Describe the blood supply output to the liver. |
|
Definition
| -via hepatic vein to caudal vena cava |
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Term
| What is the largest internal organ in the body? |
|
Definition
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Term
| What percentage of the overall BW is the liver in a carnivore? In an omnivore? Herbivores? |
|
Definition
-carnivore: 2-3%
-omnivore: 2%
-herbivore: 1-1.5% |
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Term
| What are some of the functions of the liver? |
|
Definition
-bilirubin metabolism
-bile acid metabolism
-carb metabolism
-lipid metabolism
-xenobiotic metabolism
-protein synthesis & ammonia metabolism
-filtration of blood by Kuppfer cells (immune) |
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Term
| Describe the directional blood flow in the liver? |
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Definition
| -blood enters lobules in portal regions and flows toward centrilobular region |
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Term
| Describe the regions of the lobular style of hepatic division. |
|
Definition
-lobule = hexagon
-periportal, midzonal, centrilobular |
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|
Term
| Describe the regions of the acinar architecture of hepatic division. |
|
Definition
-RAppaport's Zones:
-1: periportal
-2: midzonal
-3: centrilobular |
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|
Term
| What is the Space of Disse? |
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Definition
| -space b/n hepatocytes & sinusoid |
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Term
| What is the major exocrine function of the liver? |
|
Definition
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Term
| What are the three purposes of bile synthesis? |
|
Definition
-excretory: cholesterol, bilirubin, metabolized xenobiotics
-lipid digestion
-ingesta pH neutralization |
|
|
Term
| How is bile converted to urobilinogen? |
|
Definition
|
|
Term
| After bile is converted to urobilinogen, what does it do? |
|
Definition
-reabsorbed from GI: out in bile or urine
-oxidized to Stercobilin: out in feces |
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|
Term
|
Definition
| -maintain cholesterol homeostasis, stim bile flow & digestion and aid fat/fat soluble vitamin absorption |
|
|
Term
| Where are bile acids synthesized? |
|
Definition
|
|
Term
| Where are bile acids reabsorbed? |
|
Definition
| -in ileum: enterohepatic circulation (95%) |
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Term
|
Definition
| -chemical that is foreign to system |
|
|
Term
| What do hepatocytes do with xenobiotics? |
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Definition
| -they are lipophilic substances that are converted to water-soluble forms for excretion in bile or urine via cytochrome p450 enzymes |
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|
Term
| What is the most important plasma protein? |
|
Definition
|
|
Term
| Approximately what percentage of body proteins are synthesized in the liver? |
|
Definition
|
|
Term
|
Definition
| -liver converts ammonia (AA catabolism) to urea |
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|
Term
| How does the liver have an immune function? |
|
Definition
| -portal blood/draining GI tract => Kupffer cells attack infectious agents/endotoxins/foreign materials => hepatocytes pdc acute phase proteins |
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|
Term
| Are congenital hepatic cysts important? From what do they originate? |
|
Definition
-differentiate from parasitic cestode cysts
-originate from bile duct or capsule |
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|
Term
| Which species and corresponding breeds are predisposed to congenital polycystic dz? |
|
Definition
-dogs: West Highland White and Cairn terriers
-CAts: persians |
|
|
Term
| Are diaphragmatic hernias congenital or acquired? Describe their affects. |
|
Definition
-either congenital or traumatic
-displaced lobe may be congested or shrunken and fibrotic |
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Term
| What is the most common cause of hepatic rupture? |
|
Definition
-trauma
-can also occur spontaneouly in enlarged, dz livers |
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Term
| Which species are most commonly affected by hepatic torsion? What affects do they have? |
|
Definition
-pigs and dogs
-result in infarction of the affected lobe |
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Term
| Which species are most often affected by tension lipidosis? What causes it? Is it important? |
|
Definition
-cattle and horses
-capsular tension impedes blood flow and hypoxia results in lipidosis
-no functional significance |
|
|
Term
| Which species are most often affected by capsular fibrosis? What is it? What is cause? |
|
Definition
-horses
-discrete fibrous tags on diaphragmatic surface of liver
-proposed causes are non-septic peritonitis and parasitic nematode migration tracts |
|
|
Term
| Describe the common post-mortem changes that occur in the liver? |
|
Definition
-autolysis is rapid
-pale regions = bacterial degradation
-blue-green discoloration from H2SO4 pdn
-rib impressions
-bile discoloration of adjacent liver, intestine, boddy wall, etc |
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|
Term
|
Definition
| -dec O2 carrying capacity of the blood results in hypoxia of centrilobular hepatocytes |
|
|
Term
| What does an anemic liver look like grossly? |
|
Definition
| -enhanced lobular pattern |
|
|
Term
| What are congenital portosystemic shunts? |
|
Definition
| -abnormal vessel that allows portal blood to bypass liver and drain into systemic circulation |
|
|
Term
| What are the two types of congenital portosystemic shunts? |
|
Definition
| -intraheptaic or extrahepatic |
|
|
Term
| Describe an intrahepatic congenital portosystemic shunt? IN which animals is it most common? |
|
Definition
-often due to persistent patent ductus venosus
-most commonin large breed dogs |
|
|
Term
| Describe an extraheptic congenital portosystemic shunts? In which animals is it most common? |
|
Definition
-portal vein to caudal vena cava or azygous vein
-most common in small breed dogs |
|
|
Term
| What are the effects of congenital portosystemic shunts (PSS)? |
|
Definition
-stunted growth
-hepatic encephalopathy
-atrophied (small) liver
-anorexia, vomiting, hypersalivation
-normal portal vein pressures
-no ascites |
|
|
Term
| How do we diagnose congenital PSS? |
|
Definition
-vascular anastomoses are difficult to ID w/out aid of antemortem imaging
-CANNOT BE DX BY LIVER BIOPSY ALONE |
|
|
Term
| What causes the hepatic encephalopathy of congenital portosystemic shunts? |
|
Definition
| -ammonia is not broken down to urea |
|
|
Term
| What is microvascular dysplasia? |
|
Definition
-microscopic vascular anomaly that shunts blood from portal system to central vein
-may occur with gross shunt or alone |
|
|
Term
| What are the effects of a microvascular dysplasia? |
|
Definition
-stunted growth
-poor muscle development
-partial anorexia, vomiting
-depression, seizures, blindness, etc |
|
|
Term
| Okay so the effects of MVD and PSS look really similar. Which clinical sign is only seen w/ MVD? |
|
Definition
|
|
Term
| What are the major differences b/n portosystemic shunts and microvascular dysplasia? |
|
Definition
-PSS: imaging reveals abnormal vessels & NO ASCITES
-MVD: imaging does not reveal abnormal vessels, ascites possible |
|
|
Term
| What causes portal hypertension? |
|
Definition
| -disturbance of blood flow thru the portal v, liver, sinusoids, and/or hepatic vein |
|
|
Term
| Describe prehepatic portal hypertension. |
|
Definition
-impaired blodo flow through protal vein
-may be due to thrombosis or neoplastic invasion |
|
|
Term
| Describe intrahepatic portal hypertension. |
|
Definition
-inc R to sinusoidal blood flow
-often due to chronic liver dz: inc collagen, altered lobular architecture assoc w/ chronic inflammation of liver |
|
|
Term
| Describe posthepatic portal hypertenion. |
|
Definition
-inc R to venous outflow thru epatic v: caudal vena cava, right heart
-leads to passive hepatic congestion
-usually due to right-sided cardiac compromise or ovstruction of vena cava |
|
|
Term
| What does acute passive hepatic congestion look like grossly? |
|
Definition
-enlarged, engorged liver
-exudes blood on cut surface
-distension and congestion of centrilobular areas: dark red |
|
|
Term
| What does subacute passive congestion of the liver look like grossly? |
|
Definition
-hepatic enlargement: rounded margins, bulging cut surface
-leaky, congested sinusoids exude fluid rich in clotting factors
-fibrin encasement of liver
-fibrin strands and sheets b/n liver lobes
-ascites |
|
|
Term
| What does chronic passive hepatic congestion look like grossly? |
|
Definition
-enhanced lobular pattern: nutmeg liver
-atrophy and loss of centrilobular hpatocytes
-congested centrilobular areas = red
-fatty degeneration of periportal hepatocytes (paler, tan to yellow)
-fibrosis in chronic and severe cases: centrilobular and capsular |
|
|
Term
| What is acquired portosystemic shunting? |
|
Definition
| -shunt from mesenteric vv (multiple, thin-walled vessels) to caudal vena cava: bypass liver |
|
|
Term
| What is acquired portosystemic shunting secondary to? |
|
Definition
| -develop secondary to chronic liver dz causing portal hypertension: except for passive congestion due to post-hepatic obstruction |
|
|
Term
| What is telangiectasis? In which spp is it common? |
|
Definition
-marked dilation of snusoids w/ accumulation of pools of blood
-variably sized dark bluish-red foci
-cattle and old cats |
|
|
Term
| IS hepatic infarction common or no? What does it look like? |
|
Definition
-infrequent
-sharply delineated and dark red or pale, occur at margin of the liver |
|
|
Term
| What causes hepatocellular atrophy? What does it look like? |
|
Definition
-illness, starvation, congenital PSS or MVD
-livers retain normal shape but are small, dark, and firmer than normal while capsule may seem too big and show fine wrinkles |
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