Organisation and Function of the Liver

Question 1

State Courvoisier’s Law.

Answer 1

In the presence of an enlarged gallbladder that is non-tender and accompanied with mild jaundice, the cause is unlikely to be gallstones.

Question 2

What is Calot’s triangle?

Answer 2

It is the triangular space that is dissected in a cholecystectomy to identify a window to safely expose the gallbladder. Demarcated by: common hepatic duct, cystic duct and the cystic artery

Question 3

Where is the origin of the liver and biliary system in the gut tube?

Answer 3

Distal part of the foregut and the proximal midgut

Question 4

What system is used to describe liver development?

Answer 4

Carnegie System - 23 stages - first 60 days of development

Question 5

What is the septum transversum?

Answer 5

A thick mass of cranial mesenchyme that gives rise to parts of the thoracic diaphragm and ventral mesentery of the foregut - the septum transversum arises from the mesoderm

Question 6

Around when does the liver bud become apparent?

Answer 6

29 days

Question 7

What three structures form from the initial endodermal sprout?

Answer 7

Liver, Gallbladder and Ventral bud of the pancreas

Question 8

When does the liver rotate to the right?

Answer 8

10 weeks

Question 9

What proportion of the blood supply to the liver is via a) hepatic portal vein and b) hepatic artery proper?

Answer 9

Hepatic portal vein - 80% Hepatic artery proper - 20% The liver receives 25% of the cardiac output

Question 10

Describe the Couinaud classification of the liver segments.

Answer 10

8 functionally independent segments - starting with 1 centrally and then going clockwise. Each segment can be resected without damaging the remaining segments.

Question 11

State the five main cell types of the liver?

Answer 11

Hepatocytes Endothelial Cells (sinusoidal) Cholangiocytes Hepatic Stellate Cells Kupffer Cells

Question 12

Where is bile produced?

Answer 12

Hepatocytes (80%) And, to a lesser extent, in the cholangiocytes (20%)

Question 13

Describe the morphological divisions of the liver.

Answer 13

Divided into lobules and portal tracts/triads

Question 14

Describe the functional divisions of the liver.

Answer 14

Acini, blood flow, bile flow

Question 15

What is a lobule?

Answer 15

An area of the liver that is at a HISTOLOGICAL scale. Hexagonal.

Question 16

What are the three areas of a lobule?

Answer 16

Centrilobular Midzonal Periportal

Question 17

What does the portal triad consist of?

Answer 17

Branch of the hepatic portal vein Branch of the hepatic artery Bile duct

Question 18

Describe the path of the blood flow through a lobule.

Answer 18

The blood flows towards the central vein

Question 19

What is that shape of an acinus and what are its three regions?

Answer 19

Diamond Periportal Transition zone Pericentral

Question 20

What are the roles of zone 1 and zone 3?

Answer 20

Zone 1 - gluconeogenesis, oxidation of fatty acids and cholesterol synthesis Zone 3 - glycolysis, lipogenesis and P450 based drug detoxification

Question 21

Describe the cytological features of a hepatocyte.

Answer 21

Hepatocytes are LARGE cells and they have a PALE + ROUNDED nucleus

Question 22

Describe the cytological features of hepatic stellate cells and Kupffer cells.

Answer 22

They appear to be found in the sinusoids They have a flat, dense nucleus

Question 23

State four main functions of the liver.

Answer 23

Protein, Carbohydrate and Fat Metabolism Detoxification

Question 24

Describe the lipid metabolism function of hepatocytes.

Answer 24

Triglyceride metabolism - synthesis of fatty acids converted to triglycerides and lipoproteins for transport to the cells requiring energy Digested triglyceride chylomicron remnants processed into lipoproteins Bile acid production

Question 25

What are the roles of hepatic stellate cells?

Answer 25

• Vitamin A storage
• Production of fibrous tissue (responsible for cirrhosis)

Question 26

What are the roles of sinusoidal endothelial cells?

Answer 26

Fenestrated - allows lipids and other large molecule movement to and from hepatocytes

Question 27

What are the roles of Kupffer cells?

Answer 27

Resident phagocytes Secretion of cytokines that activate hepatic stellate cells

Question 28

What bud are the biliary structures formed from?

Answer 28

Pars cystica

Question 29

What does ERCP stand for?

Answer 29

Endoscopic retrograde cholangiopancreatography

Question 30

On the ultrastructure of hepatocytes: how are the RER and Golgi Apparatus involved in protein metabolism?

Answer 30

• RER - needed for synthesis: o Non-essential amino acids, clotting factors, albumin • Golgi Apparatus - needed to pack for secretion

Question 31

On the ultrastructure of hepatocytes: name three structures involved in carbohydrate metabolism. How can carbohydrates be metabolised?

Answer 31

• SER • Mitochondria • Cytoplasmic enzymes • Needed for glycolysis, gluconeogenesis, glycogenolysis, glycogenesis

Question 32

On the ultrastructure of hepatocytes: name three structures involved in lipid metabolism. How can lipids be metabolised?

Answer 32

• SER • Peroxisomes • Mitochondria • Needed for triglyceride metabolism and bile acid production

Question 33

On the ultrastructure of hepatocytes: name two structuress involved in detoxification. How does detoxification occur?

Answer 33

Detoxification • Lysosomes • SER Metabolise/modify/detoxify exogenous compounds