Liver Stucture And Function

Question 1

List some of the functions of the liver

Answer 1

Amino acid, carbohydrates and lipid metabolism
Plasma protein and enzyme synthesise
Production of bile
Detoxification
Storage of proteins, glycogen, vitamins and metals
Production of some clotting factors
Immune functions

Question 2

The hepatic artery delivers oxygenated blood to the liver. How much of the total liver blood supply does the hepatic artery comprise?

Answer 2

30-40%

Question 3

The portal vein delivers deoxygenated blood directly from the GI tract, pancreas and spleen to the liver. How much of the total liver blood supply does the portal vein comprise?

Answer 3

60-70%

Question 4

Which blood vessel drains the liver?

Answer 4

Hepatic vein

Question 5

What vessels comprise the portal triad?

Answer 5

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

Question 6

Why is the blood in the hepatic portal vein at a very low pressure?

Answer 6

Because it has already passed thorough the capillary beds in the GI tract

Question 7

What is the name of the specialised capillaries which connect the hepatic artery and portal vein to the hepatic vein?

Answer 7

Liver sinusoids

Question 8

What shape are the hepatic lobules?

Answer 8

Hexagonal

Question 9

Where in the hepatic lobules does the branch of the hepatic vein lie?

Answer 9

In the centre of the lobule

Question 10

Hepatocytes are arranged in plates. T/F?

Answer 10

True

Question 11

On a histology slide how can you differentiate the three elements of the portal triad?

Answer 11

The epithelium of the bile duct has the thickest nuclei so stains a dark blue
The portal vein is larger and has thinner walls than the hepatic artery

Question 12

At what surface of the hepatocyte does exchange of material between cell and blood supply occur?

Answer 12

Sinusoidal surface

Question 13

What occurs at the canalicular surface of the hepatocyte?

Answer 13

Bile, produced by the hepatocyte, is drained into the canaliculi at this surface

Question 14

The endothelium of the liver sinusoids is specialised to facilitate the exchange of material. In what ways does it differ from other endothelium?

Answer 14

It has fenestrations

It lacks a complete basement membrane so that there is less fibrous tissue to impede the exchange of material

Question 15

In addition to hepatocytes, what other cells exist in the liver?

Answer 15

Kupffer cells (macrophages)
Perisinusoidal cells which store fat and fat soluble vitamins
Liver associated lymphocytes
Endothelial cells

Question 16

What is the basement membrane of the liver sinusoids comprised of?

Answer 16

Parenchyma, reticulin

Question 17

How is bile transported from hepatocyte to the common hepatic duct?

Answer 17

From the hepatocyte bile travels in canaliculi which become bile ductules and then bile ducts which run through the portal triad to eventually fuse to form the hepatic bile duct

Question 18

Which protein transports unconjugated bilirubin from the breakdown of red blood cells to the liver?

Answer 18

Albumin

Question 19

In what form is bilirubin secreted in faeces?

Answer 19

Stercobilinogen

Question 20

In what form is bilirubin secreted in urine?

Answer 20

Urobilogen

Question 21

Bilirubin is conjugated in the liver then secreted in bile and eventually leaves the body in…?

Answer 21

Mostly faeces but also some in urine

Question 22

What are the four lobes of the liver?

Answer 22

Caudate
Quadrate
Right
Left

Question 23

What is the name of the fibrous capsule which surrounds the liver?

Answer 23

Glissons capsule

Question 24

What is the round ligament of the liver a remnant of?

Answer 24

The embryological umbilical vein

Question 25

What functions are carried out particularly by the cells in zone one of the liver acini?

Answer 25

Citric acid cycle
Fatty acid oxidation
Gluconeogenesis
Urea synthesis
Production and excretion of bile

Question 26

What functions are carried out particularly by cells in zone three of the liver acini?

Answer 26

Glycolysis
Glutamine synthesis
Xenobiotic metabolism

Question 27

There is cross talking between the metabolic pathways of the liver. T/F?

Answer 27

True

Question 28

How are carbohydrates stored in the liver?

Answer 28

As glycogen

Question 29

What is the term for the release of carbohydrates by the liver?

Answer 29

Glycogenesis

Question 30

What is gluconeogenesis?

Answer 30

The synthesis of glucose from other sources such as lactate, pyruvate, glycerol and alanine

Question 31

Where in a hepatocyte does beta oxidation occur?

Answer 31

Mirochondria

Question 32

What are the potential products of beta oxidation in hepatocytes?

Answer 32

Fatty acids
Triglycerides
Phospholipids
Cholesterol
Lipoproteins

Question 33

What are fatty acids produced by the liver used for?

Answer 33

The production of ATP via the citric acid cycle

Question 34

What is cholesterol, synthesised by the liver, used for?

Answer 34

Synthesis of membranes
Synthesis of hormones
Synthesis of other materials

Question 35

What toxic compound is produced from normal amino acid metabolism and is converted to urea in the liver?

Answer 35

Ammonia

Question 36

Why is hyperammonemia dangerous?

Answer 36

It can lead to brain damage

Question 37

In phase one of detoxification toxic compounds are converted to hydroxylated or carboxylated non toxic compounds in the smooth endoplasmic reticulum of hepatocytes via which molecule?

Answer 37

Cytochrome 450

Question 38

What happens in phase two of detoxification by hepatocytes?

Answer 38

Conjugation with glucuronic acid, acetyl or methyl radicals, glycine, taurine of sulphate