The Liver: Anatomy and Function

Question 1

The two lobes of the liver are separated by which ligament?

Answer 1

Falciform ligament

Question 2

Which lobe of the liver is bigger?

Answer 2

The right lobe

Question 3

What are the functional units of the liver?

Answer 3

lobules (UK) or acinus (US)

Question 4

How many sections could a surgeon separate a liver into?

Answer 4

8

Question 5

Where does the liver receive blood from and in what proportions/

Answer 5

Portal vein - venous blood from gut (75%)

Hepatic artery - arterial blood (25%)

Question 6

What is the venous drainage of the liver?

Answer 6

Blood enters, mixes in the sinusoids and drains via hepatic veins into the IVC near the right atrium

Question 7

What is the functional significance of the arrangement of lobules and their blood supply?

Answer 7

a hepatocyte is never more than one cell away from blood supply

Question 8

What are the smallest channels where blood can mix in the liver?

Answer 8

sinusoids

Question 9

True or False?

• Liver cells are non-polarised cuboidal cells
• They have a low mitotic index

Answer 9

False - they are polarised polyhedral cells

True

Question 10

What cell type makes up biliary epithelium?

Answer 10

polarised cuboidal or columnar epithelial cells

Question 11

What is the function of the dense basement membrane in biliary epithelium?

Answer 11

prevent bile from coming into contact with the liver and damaging it

Question 12

What is the function of squamous epithelial cells that line the hepatic vasculature?

Answer 12

protect the parenchyma from blood cells, bacteria and viruses
filter fluids
As well as normal endothelial functions e.g. ant-chromogenic, coagulation, leukocyte traffic, selective uptake, scavenging of waste products

Question 13

What are Kupffer Cells?
Where are they found?
What are their functions?

Answer 13

Hepatic macrophages located within the sinusoids
Phagocytosis, regulation of microcirculation, removal of endotoxin
Can produce cytokines, present antigen and stimulate immune response

Question 14

What are stellate cells?
By what name are they also known?
What is their function?
What is their role in fibrosis?

Answer 14

Also called Ito cells or lipocytes, perisinusoidal fat storing cells
Star shaped with multiple membrane processes
Can transform to a more fibroblast-like morphology in disease
In fibrosis, the make ECM

Question 15

What are the 2 digestive functions of the liver

Answer 15

Carbohydrate and fat metabolism

Storage of vitamins and minerals

Question 16

Where statins act and why?

Answer 16

They act in the liver to inhibit the enzyme that synthesises cholesterol

Question 17

Which vitamins are fat soluble?

Answer 17

Vitamins A, D, E and K

Question 18

What is the function of bile?

Answer 18

emulsification of fat
fat soluble vitamin uptake
excretion of some substances that cannot be cleared by kidneys (cholesterol, bilirubin)

Question 19

What is the immune function of the liver?

Answer 19

Protection against pathogen arriving in the blood
Phagocytosis of old or dying cells
Innate immune functions
Indiction of tolerance

Question 20

What are the detoxification and elimination functions of the liver?

Answer 20

urinary excretion (solubilisation of compounds)
biliary excretion (lipophilic compounds)
biotransformation of drugs
- redox reactions to make soluble (P450)
- conjugation to make water soluble
elimination of ammonia (by-product of protein metabolism)

Question 21

What useful proteins does the liver produce?

Answer 21

Albumin
Fibronectin and components of coagulation cascade
Plasminogen
Alpha-1 antitrypsin
Transferrin
Hepcidin

Question 22

What are the 3 stages of liver damage?

Answer 22

Fatty liver - deposits of fat lead to liver enlargement
Liver fibrosis - scar tissue forms
Liver cirrhosis - growth of connective tissue destroys liver cells

Question 23

What are the 3 complications of liver cirrhosis?

Answer 23

Renal failure
Oesophageal varices
Ascites

Question 24

What are the main drivers of cirrhosis in the EU

Answer 24

viral infection
alcohol
metabolic syndrome

Question 25

How does hepatitis cause damage?

Answer 25

Viruses selectively infect hepatocytes
Very strong immune response causes severe hepatitis
The immune system then kills the infected hepatocytes
Development of fibrosis and end stage liver failure

Question 26

How does alcohol cause cirrhosis?

Answer 26

Toxic injury –> inflammatory response