Lecture 13 Flashcards
What are the 4 main anatomical units of the liver
Hepatocytes Bile duct system Vascular system Kupffer cells
What is the functional organisation of the liver
Blood flows from portal triads around periphery towards the central vein in the centre of the lobule Bile drains from hepatocytes to portal triads at centre
What are periportal hepatocytes affected by
Direct acting toxins
What are periacinar hepatocytes affected by
Activated toxins, hypoxia
What is hepatobiliary injury
Injurious agents may enter liver and biliary system by - Haematogenous - Retrograde biliary entry from GIT - Direct penetration from trauma
What may hepatobiliary injury cause
Inflammation, degeneration (reversible) or apoptosis or necrosis (irreversible)
What are the defence towards hepatobiliary injury
Kupffer cells in sinusoids Biliary tree - Mucosal immunity: IgA - Flow of bile - Sphincter at end of common bile duct
What is seen grossly with acute cellular degeneration: Acute swelling
Liver is pale and swollen
What is seen histologically with acute cellular degeneration: acute swelling
Cells are pale, swollen and finely vacuolated
What do you see grossly with fatty change
Liver is pale, yellowish, large, rounded edges
What do you see histologically with fatty change
Cells have large lipid vacuoles, nuclei pushed to the side
What is the nature and distribution of degeneration, necrosis and inflammatory lesions in the liver affected by
Route of entry Type of injurious agent Predilection for particular cell types Host response
What is the patterns of hepatocellular degeneration and necrosis
Random - no pattern to the damage - e.g. haematogenous infectious agent Zonal patterns - Periaciner/centrolobular - toxins that require activation, anaemia, heart failure - Midzonal - Massive - necrosis of entire lobule
What is cholecystitis
Inflammation of gall bladder
When classifying liver/biliary disease, what should you consider
- Distribution and pattern of involvement - Types of inflammatory cells if present - Evidence of degeneration, necrosis or fibrosis - Evidence of regeneration - Presence of etiologic agent - Severity - Duration
What is seen in acute hepatitis
Often random distribution of inflammation - Often neutrophils esp if bacterial - May be lymphocytes if viral - Hepatocellular necrosis +/- apoptosis
What is seen in chronic hepatitis
Persistence of antigenic stimulus - Accumulation of mononuclear cells - Maybe also be neutrophils present - Fibrosis and biliary hyperplasia - May get regeneration of hepatocytes
What is cholangitis
Inflammation centred on biliary tract
What is cholangiohepatitis
Inflammation around portal triads that also extends into liver parenchyma
What are the responses of the liver due to injury
Regeneration Fibrosis Biliary hyperplasia Cirrhosis Hepatic failure
What is the cirrhosis liver
Diffuse process characterised by fibrosis and the conversion of the normal liver architecture into structurally abnormal lobules
What are the responses of liver injury (fibrosis)
- Increased ECM within the liver - Common in chronic/repetitive liver damage - Often severely impairs hepatic function - Pattern may assist identification of type of insult: periacinar, periportal, multifocal
What are the responses of liver injury (bile duct hyperplasia)
- Proliferation of new bile ducts in periportal area - Nonspecific response to liver injury
What are the major determinants of the final outcome of liver injury
- Whether hepatocellular injury is sustained or repetitive - Severity and extent of fibrosis - How much of the liver’s framework remains on which regeneration can take
What does hepatocellular loss result in
Small liver
What does hepatocellular hyperplasia result in
Randomly distributed regenerative nodules
What is variable fatty change due to
Disturbances in liver lipid metabolism
Acute cellular degeneration: acute swelling in liver
Acute swelling in liver
Fatty change
Fatty change
Random hepatocellular injury
Zonal hepatocellular injury: accentuation of the normal lobular pattern
Zonal hepatocellular injury: periacinar/centrolobular necrosis
Massive necrosis
Periportal necrosis
Midzonal necrosis
Massive necrosis
Massive necrosis
Regeneration: stem cell hyperplasia and biliary hyperplasia
Chronic nodular hyperplasia
Periportal fibrosis and bile duct hyperplasia
Cirrhosis
Cirrosis
Cirrhosis
