Patterns of liver disease

Question 1

Label structures A-G

Answer 1

A - hepatocytes

B - hepatic portal vein

C - heptatic artery

D - central vein

E - bile caniculi

F - bile duct

G - venous sinuses

Question 2

How is liver parenchyma split up?

Answer 2

Into 3 zones:

• Zone 1 - periportal - closest to afferent blood supply
• Zone 2 - midonal - blood gradually deoxygenates
• Zone 3 - centrilobular - closest to terminal hepatic vein, area most prone to hypoxic damage

Question 3

What is the liver protected by?

Answer 3

Skin, ribcage, kupffer cells

Question 4

What protects the biliary tree?

Answer 4

• Mucosal secretion of IgA from GI plasma cells
• Terminal sphincter

Question 5

What are the 3 portals of entry into the liver?

Answer 5

1. Direct extension
2. Haematogenous
3. Retrograde biliary transport

Question 6

What are the 6 mechanisms of liver injury?

Answer 6

1. Metabolic bioactivation of chemicals
2. Stimulation of autoimmunity
3. Stimulation of apoptosis
4. Disruption of calcium homeostasis
5. Bile canicular injury
6. Mitochondrial injury

Question 7

What are the main targets of liver injury?

Answer 7

Epithelial cells; hepatocytes, biliary epithelium

Question 8

What are the 2 types of liver injury?

Answer 8

1. Sub-lethal/reversible - cell swelling and atrophy
2. Lethal/irreversible - necrosis and apoptosis

Question 9

What are the 3 patterns of hepatocellular degeneration?

Answer 9

Random, zonal and massive.

Question 10

What are the characteristics of random necrosis?

Answer 10

• multifocal necrosis
• single/small no. cells affected
• caused by infectious agents

Question 11

What are the characteristics of zonal necrosis?

Answer 11

• enlarged, rounded liver
• specific zones degenerate

Question 12

What are the characteristics of massive necrosis?

Answer 12

Affects entire lobule/contiguous lobules

Question 13

What type of necrosis is shown here?

Answer 13

Random

Question 14

What type of necrosis is shown here?

Answer 14

Zonal

Question 15

What type of necrosis is shown here?

Answer 15

Massive

Question 16

What are the 3 responses of the liver to injury?

Answer 16

Regeneration, fibrosis, biliary hyperplasia

Question 17

Describe the processes that occur during regeneration

Answer 17

• Hepatocytes, biliary epithelium, endothelium and sinusiodal linings replicate
• Existing lobules increase in size; sometimes new lobule will form
• Proliferation of adjacent hepatocytes in individual areas/small foci of necrosis
• Proliferation of hepatocyte stem cells
• Release of growth factors; hepatocyte growth factor, TGF-a

Question 18

Describe the processes that occur during fibrosis

Answer 18

• Occurs during chronic injury
• Pattern of fibrosis may suggest underlying cause (centrilobular can indicate chronic toxic change, periportal can indicate chronic inflammatory changes)

Question 19

Describe the processes that occur during biliary hyperplasia

Answer 19

• Proliferation of bile ducts and periportal parenchyma
• Usually seen in longstanding liver injury
• Mechanism is unknown

Question 20

What is meant by ‘liver cirrhosis’?

Answer 20

Diffuse fibrosis with hyperplastic nodule formation (totl abscence of any norma lobular architecture)

Question 21

State 6 causes of liver cirrhosis

Answer 21

1. Chronic toxicity
2. Chronic cholangitis
3. Chronic congestion
4. Chronic hepatitis
5. Inherited disorders of metal metabolism
6. Idiopathic

Question 22

What are the effects of liver cirrhosis?

Answer 22

• Decreased albumin production
• Hypoproteinaemia
• Decreased oncotic pressure
• Oedema