L8- Liver pathology

Question 1

What are the functions of the liver?

Answer 1

Metabolic= Glucose homeostasis, glycogensis and gluconeogenesis
Storage= Glycogen, triglycerides, lipid, vitamins
Catabolic processes= hormones, detoxification of xenobiotics
Excretory function= bile

Question 2

What do the different surfaces of hepatocytes do?

Answer 2

• Sinusoidal surface- exchange surface in contact with blood, microvilli
• Biliary surface- canalicular, specialised membrane where bile is secreted
• Lateral surface- tight junctions between hepatocytes

Question 3

What is the structure of the hepatic sinusoid?

Answer 3

• Specialised fenestrated endothelia with no basement membrane to allow easy interchange of substances
• Nisse space containing cells and stroma
• Stellate cells containing fat droplets
• Kupffer cells are specialised macrophages

Question 4

What is zonal heterogeneity?

Answer 4

The variation of the sizes and quantities of structures in the liver depending on whether they are in the periportal or centrilobular areas

Question 5

What are the patterns of hepatocellular injury and hepatitis?

Answer 5

• Cholestasis- abnormal accumulation of bile
• Steatosis- accumulation of fat droplets in hepatocytes
• Fibrosis- leads to cirrhosis (islands of regenerative hepatyocytes)

Question 6

What can hepatocellular injury lead to?

Answer 6

• Hepatic failure (loss of hepatic function)
• Acute (necrosis)
• Chronic liver disease
• Metabolic dysfunction
• Jaundice and cholestasis

Question 7

What are consequences of infection with hepatitis virus?

Answer 7

• Complete clearance of infected cells and restoration of normal tissue architecture
• Persistent or chronic infection
• Oncogenic effect- material of virus integrates into cell DNA

Question 8

What happens in cirrhosis?

Answer 8

• Takes years of chronic hepatitis to develop
• Hepatocyte loss
• Vascular obliteration
• Fibrosis matrix deposition
• Loss of architectural/functional organisation

Question 9

What are the complications of cirrhosis?

Answer 9

• Parenchymal liver failure
• Endocrine effects
• Portal flow reduced due to fibrosis resulting in portal hypertension
• Cholestasis (interference with bile excretory functions)

Question 10

What are the clinical consequences of cholestasis?

Answer 10

• Retention of bilirubin, bile acids and cholesterol
• Jaundice or icterus
• Fatigue

Question 11

What are causes of steatosis?

Answer 11

• Fatty liver disease
• Alcoholics
• Metabolic (insulin resistance): obesity, diabetes, hyperlipidaemia
• Drugs, toxics, surgical procedures