YR3 8 L HO1 Flashcards
Liver Structure/Function - Zone 1 oxygen rich blood
Hepatic artery
Liver Structure/Function - Zone 1 nutrient rich blood
Portal vein
Liver Structure/Function - Zone 1 Blood vessels origin
Portal triad
Liver Structure/Function - Zone 1 is active in
Plasma protein synthesis & general protein metabolism
Liver Structure/Function - Zone 3 is last to
Receive oxygen & nutrients and close to the central vein
Liver Structure/Function - Zone 3 is rich in
Smooth ER and mixed function oxidases e.g. cytochrome P450
Liver Structure/Function - Bile movement
Blood moves to the centre, bile movies opposite
Liver Functions
1)Metabolic 2)Bile pigments, bile salts, cholesterol 3)Phagocytosis 4)Extramedullary haemopoiesis 5)Detoxification (conjugation - lipid to water soluble)
Liver Metabolic Functions
1)Carbohydrate 2)Lipid 3)Protein 4)Plasma proteins synthesis (serum albumin, most globulins) 5)Clotting factors (fibrinogen, prothrombin, V, VII, IX, X) 6)Vitamins A, D B12 7)Fe storage
Liver Reactions to Injury
1)Regeneration 2)Fibrosis 3)Bile duct hyperplasia
Liver Rxns to Injury - Regeneration; types
Micro vs. Macronodular
Liver Rxn to Injury - Fibrosis; types
1) Biliary (portal) 2)Post-necrotic 3)Diffuse (intra/interlobular) 4)Periacinar (centrilobular)
Liver Disease - Clinical Signs
1)Jaundice (icterus) 2)Hepatogenous photosensitivity 3)Coagulopathies 4)Diarrhoea 5)Oedema, Ascities 6)Weight loss
Incidental Liver Lesions
1)Tension lipidosis 2)Capsule plaques or tags 3)Telangiectasis 4)Gall bladder anomalies
Incidental Liver Lesions - Tension lipidosis
Common in horses - caused by capsular tension. Lesion - well demarcated area of fatty change
Incidental Liver Lesions - Capsule plaques
Diaphragmatic surface of horse livers - due to strongyle migration
Incidental Liver Lesions - Telangiectasis
Localised dilation of sinusoids - slightly sunken foci. Common in old cats and cattle
Liver Postmortem Changes
1)Autolysis 2)Putrefaction 3)Pseudomelanosis 4)Bile imbibition 5)Haemoglobin imbibition
Liver Postmortem Changes - Putrefaction
Also called pseudonecrosis. Irregular pale tan foci which may contain gas bubbles
Liver Postmortem Changes - Advanced Putrefaction
Foci of post mortem bacterial invasion and gas production. The diffuse pallor is due to autolysis
Liver Postmortem Changes - Pseudomelanosis
Pigmentation due to iron sulphide and sulphur methaemoglobin. Proximity to intestines - the same process results in the greenish pigmentation of the abdominal wall
Liver Postmortem Changes - Bile Imbibition
Yellow/Green discolouration of the liver or any tissues adjacent to the gall bladder due to leakage
Liver Congenital Anomalies
Cysts - Differentiate from parasites/tumours (may be acquired) e.g. Congenital Biliary Cysts
Liver Displacement/Rupture
1)Diaphragm - displacement caudally, hernia 2)Torsion of lobe - Pigs, dogs; usually the left lateral lobe > causes shock & death 3)Rupture
Liver Displacement/Rupture - Rupture
Most common cause is trauma. Inflammation, fatty change and amyloidosis may predispose
Liver Pigments & Deposits
1)Melanosis 2)Lipopigments 3)Haemosiderin 4)Bile pigment 5)Indole melanins 6)Iron-porphyrin 7)Crystalloid material 8)Amloid
Liver Pigments & Deposits - Congenital Melanosis
Calves, lambs, piglets -no pathological significance
Liver Pigments & Deposits - Lipopigments; type
Yellow to Brown 1)Ceroid due to auto-oxidation of polyunsaturated fat 2)Lipofuscin - age pigment
Liver Pigments & Deposits - Lipopigments; disease
Storage disease (ceroid-lipofusinosis)
Liver Pigments & Deposits - Haemosiderin
If severe, grossly dark brown
Liver Pigments & Deposits - Haemosiderosis
1)Iron overload 2)Haemolytic anaemias 3)Copper deficiency 4)Cachexia
Liver Pigments & Deposits - Cholestasis
Greenish or orange bile oozes from cut surfaces. Distinguish from fatty liver.
Liver Pigments & Deposits - Bile Pigmentation
May be olive green to yellow ochre. Birds - green due to biliverdin 1)Cholestasis 2)Obstructive icterus
Liver Pigments & Deposits - Indole Melanin
From Pharlaris staggers & Tryptamine alkaloid. Greenish-grey: Parts of the brain & renal medulla
Liver Pigments & Deposits - Iron porphyrin
Black pigment. From Fasciola & Schistosoma spp. Infections
Liver Pigments & Deposits - Crystalloid Material
From Panicum spp. And Tribulus terrestris > Hepatogenous photosensitivity
Liver Pigments & Deposits - Amyloidosis
Secondary to chronic inflammation. Amyloid deposited in space of Disse > Hepatomegaly, pale tan, predisposed to rupture
Liver - Reversible Injury (Degeneration)
1)Cell swelling 2)Fatty change
Reversible Injury - Cell Swelling
Aka ‘cloud swelling’ or ‘hydropic degeneration’ Grossly: the liver may be emlarged and light brown
Reversible Injury - Fatty Change
Gross: Tan, creamy-yellow, enlarged w/ rounded edges, friable in consistency and often greasy to touch with a small amt. of bile oozing out of cut surface. Micro: Smooth edges of fat vacuoles
Reversible Injury - Fatty Change; diseases
1) Diabetes 2)Pregnancy ketosis
Causes of Fatty Liver
1)Physiological 2)Pathological
Causes of Fatty Liver - Physiological
1)Fasting 2)Pregnancy (esp. ruminants) 3)Lactation (cow)
Causes of Fatty Liver - Pathological
1)Genetic - hyperlipaemia in horses, cats 2)Metabolic - pregnancy toxaemia & ketosis, diabetes mellitus, hypothyroidism, hyperarenocorticism 3)Deficiencies - anaemia, choline, cobalt/vitB12 4)Toxicities - phosphorus, aflatoxin, myoporum spp.
Ovine White Liver Disease
Ill thrift, photosensivity due to cobalt/vitB12 deficiency
Changes in Liver &/ Hepatocyte Size - Atrophy
Due to shunts, malnutrition, ‘portal streaming’
Changes in Liver &/ Hepatocyte Size - Hepatomegaly
1)Chronic passive congestion 2)Cell swelling 3)Fatty change 4)Amyloidosis 5)Diffuse inflammation 6)Diffuse neoplasia
Patterns of Liver Necrosis
1)Single cell 2)Focal 3)Centrilobular 4)Midzonal 5)Periportal 6)Paracentral 7)Massive 8)Pannecrosis
Patterns of Liver Necrosis - Focal>Small
Small necrotic foci - Scattered, Multifoci, Need light to see. Causes - Bacterial septicaemia e.g. salmonellosis, Virus e.g. EHV1, Protozoa e.g. Toxoplasma
Patterns of Liver Necrosis - Focal>Large
Foci can be >20mm and coalescing. Causes - Necrobacillosis by Fusobacterium necrophorum
Patterns of Liver Necrosis - Centrilobular (Periacinar)
Causes - hypoxia, passive congestion, exogenous toxins
Patterns of Liver Necrosis - Zonal
Causes - 1)various plant toxicities 2)polychlorinated biphenyl (PCB) toxicity
Patterns of Liver Necrosis - Periportal
Causes - 1)phosphorus poisoning 2)acute sporidesmin toxicity (facial eczema)
Patterns of Liver Necrosis - Massive/Submassive
Causes - 1)Serum hepatitis in horses 2)Cardiac failure in pigs 3)Acute iron toxicity in piglets 4)Acute parenteral copper toxicity in calves 5)Hepatosis dietetica in pigs
Hepatosis dietetica in pigs
Deficiences in VitE/Se, S-containing aa or choline. Often diet high in polyunsaturated fats. Lesion - Necrotic lobules collapse, healing results in post necrotic scarring
VitE / Se Deficiency / Xs Dietary Unsaturated Fats in Pigs
1)Hepatosis dietetica 2)Muscular dystrophy 3)Mulberry heart 4)Yellow fat disease 5)Exudative diathesis 6)Fibrinoid necrosis of arterioles 7)Serous effusions
Patterns of Liver Necrosis - Pannecrosis
Liver literally a ‘bag of blood’. Outcome 1)Rift Valley fever in lambs 2)Some haemorrhagic fever in man
Circulatory Changes and Vascular Anomalies
1)Obstruction of the hepatic artery 2)Portal Vein 3)Obstruction of efferent vessels 4)Portosystemic shunts
Obstuction of the Hepatic Artery
1)Small foci of necrosis - parasitc migration 2)Large necrotic segments of the liver: Horses - Strongylus vulgaris arteritis, Cats - Aortic/hepatic arterial thrombosis
Portal Vein - Portal Streaming
Selective distribution of blood in the liver
Portal Vein - Portal Hypertension; cause
1)Severe, widespread hepatic necrosis 2)Widespread hepatic fibrosis 3)Right-sided congestive heart failure 4)Cardiac tamonade > Sequelae - Ascites (often containing fibrin)
Chronic Passive Congestion; definition
Liver swollen and darker than normal with severe ascites - the pattern on cut surface may resemble a nutmeg. The nutmeg-like appearance is due to centrilobular necrosis / fibrosis, sinusoidal engorgement and periportal fatty change
Chronic Passive Congestion; causes
1)Congestive (right) heart failure 2)Caudal vena cava thrombosis 3)Liver incarceration in diaophragmatic hernia 4)Chronic partial torsion of a lobe
Obstruction of Efferent Veins; causes
1)’Nutmeg’ liver 2)Cardiac fibrosis 3)Cyanotic induration > Chronic Passive Congestive synonyms
Portosystemic Shunts
Dog & Cats, Congenital or Acquired. High NH3 and Bile Salts, Low urea and albumin, Ammonium biurate crystals in urine. Liver is small, firm and nodular
Portosystemic Shunts - Congenital
Young runts with nervous signs (hepatic encephalopathy). Five types (intra/extra hepatic) 1)Patent ductus venosus 2)Portal vein atresia 3)Portocaval 4)Portoazygos 5)Portocaval-azygos
Portosystemic Shunts - Acquired
Portal hypertension present