Liver - Module 5

Question 1

What is excretion?

Answer 1

The removal of the waste products of metabolism in the body

Question 2

What are the 3 main products of excretion in the body?

Answer 2

1. Carbon dioxide
2. Bile pigments
3. Nitrogenous waste (urea)

Question 3

What are bile pigments formed from?

Answer 3

The breakdown of haemoglobin in the liver

Question 4

What artery and vein supply blood/take blood away from the liver?

Answer 4

HEPATIC ARTERY AND HEPATIC VEIN

Question 5

What does the hepatic portal vein do?

Answer 5

bring blood with the productions of digestion straight to the liver as a point for metabolic activities to occur

Question 6

What is the name of liver cells?

Answer 6

Hepatocyte

Question 7

Describe the structure of a hepatocyte

Answer 7

Lots of mitochondria, large nucleus and a prominent Golgi

Question 8

What happens in the sinusoids?

Answer 8

They are spaces in liver where blood from hepatic artery and hepatic portal vein mix together so that the blood from the portal vein has enough oxygen so that hepatocytes can function

Question 9

What are kuppfer cells?

Answer 9

‘Macrophages of the liver’ remove unwanted and foreign particles

Question 10

What happens when hepatocytes secrete bile?

Answer 10

Bile is secreted into canaliculi which drain the bile into ducts and eventually to gall bladder

Question 11

What are the 3 main roles of the liver?

Answer 11

1. Carbohydrate metabolism
2. Deamination of amino acids
3. Detoxification

Question 12

How is the liver involved in the metabolism of carbohydrates?

Answer 12

Hepatocytes convert glucose to glycogen (carbohydrate) and back once stimulated by insulin and glucagon

Question 13

What is transamination? Why is it useful?

Answer 13

The conversion of one amino acid into another by hepatocytes
It is useful as it overcomes issues with diet not providing the correct amino acids

Question 14

What is deamination? And why is this important?

Answer 14

The removal of amine groups from molecules
This is important as proteins cannot be stored by the body and therefore would be wasted in excretion

Question 15

The cycle of deamination os called the ornithine cycle
Describe this cycle

Answer 15

1. Hepatocytes deaminated amino acid
2. Ammonia is the product NH3 which is very toxic so is converted to orthinine
3. Ornithine is added to carbon dioxide and a water is removed making citriline
4. Citruline has NH3 added and water removed to make arginine
5. Arginine has water added to make urea

Question 16

Is urea toxic?

Answer 16

Only in high concentrations

Question 17

What is detoxification? Give 2 examples

Answer 17

When toxins are broken down in the liver

1. Hydrogen peroxide
   Hepatocytes contain catalase which splits hydrogen peroxide into water and oxygen
2. Alcohol ethanol
   Hepatocytes contain alcohol hydrogenase converting ethanol - ethanal - ethanoate which is used to produce fatty acids