The Liver

Question 0

Define hepatocyte

Answer 0

A liver cell

Question 1

Forms of nitrogenous waste

Answer 1

Ammonia
Urea
Uric acid

Question 2

The blood supply of the liver.

Answer 2

Hepatic artery carries oxygenated blood from the aorta.
Hepatic portal vein carries blood from the small intestine rich in absorbed nutrients (much lower pressure)
Hepatic vein carries blood from the liver back to the vena cava.

Question 3

Why is the hepatic portal vein at a reduced pressure and what else may it contain?

Answer 3

The blood has already been through a capillary network with a large cross sectional area reducing pressure.
Insulin and glucagon will be present.

Question 4

Role of the bile duct

Answer 4

Carries bile secreted by hepatocytes to the gall bladder where it is stored until needed to emulsify lipids.

Question 5

Why are liver cells arranged the way they are?

Answer 5

To allow maximum contact between blood and liver cells.

Question 6

Formation of urea.

Answer 6

Excess amino acids are deaminated to form ammonia and a keto acid. The keto acid is transported to be used in respiration whilst the ammonia is turned into urea via the ornithine cycle.

Question 7

The ornithine cycle

Answer 7

Ammonia+O2+ornithine goes to citralline+H2O
citralline+ ammonia goes to arginine+H2O
H2O+arginine = urea CO(NH2)2 + ornithine

Question 8

Detoxification of alcohol

Answer 8

Ethanol plus ethanol dehydrogenase gives ethanal and reduced NAD (NADH).
Ethanal plus ethanal dehydrogenase gives acetate and more reduced NAD.
Acetate plus coenzyme A gives Acetyl coenzyme A
Acetyl coenzyme A and reduced NAD are used in respiration.