Liver

Question 1

What are the main metabolic waste products in mammals?

Answer 1

• CO2
• Bile pigments
• Nitrogenous waste (urea)

Question 2

How does the liver’s blood supply work?

Answer 2

• Hepatic portal vein delivers products of digestion to the liver.
• The hepatic artery delivers oxygenated blood.
• Both mix in the sinusoid and flow into the hepatic vein.

Question 3

Describe the structure of the sinusoid.

Answer 3

• Hepatic portal vein and hepatic artery both allow blood to flow into the sinusoid, then flows out through the hepatic vein.
• Hepatocytes produce bile which drains out of bile ducts via the bile canaliculus.
• Kuppfer cells are tissue bound macrophages which ingest foreign particles and help the breakdown of blood into the canaliculi.

Question 4

What are the roles of the liver?

Answer 4

• Carbohydrate metabolism
• Deamination of XS AAs
• Transamination
• Detoxification

Question 5

How is the liver involved in carbohydrate metabolism?

Answer 5

• Glycogen and glucose interconversion depending on blood glucose conc.

Question 6

Why is transamination important?

Answer 6

• Diet does not always meet required balance of AAs, transamination allows XS AAs to be converted into others which are lacking.

Question 7

Describe the process of deamination

Answer 7

• AAs have their NH2 group removed. Becomes ammonia.
• The NH3 combines with CO2 to form urea in the orthenine cycle for excretion.
• The remainder of the AA can be used in respiration

Question 8

How is ethanol detoxified?

Answer 8

• Ethanol is converted to ethanal by ethanol dehydrogenase.
• This is converted into ethanoate.