5.1.2 Excretion

Question 1

What is the function of the hepatic portal vein?

Answer 1

Brings blood containing products of digestion into the liver from the intestines

Question 2

What is the function of the hepatic artery?

Answer 2

Brings oxygenated blood to the liver from the heart
(is a narrow vessel as pressures are lower since blood travelled a long distance)

Question 3

What is the function of the hepatic vein?

Answer 3

Carries deoxygenated blood away from the liver to the heart

Question 4

What is the function of Kupffer cells?

Answer 4

Macrophages which digest foreign material and have a role in the immune system

Question 5

What is the bile canaliculus?

Answer 5

Hepatocytes secrete bile here and from there it is drained into gall bladder to be stored

Question 6

What is the importance of sinusoids?

Answer 6

Allows blood from the hepatic artery and hepatic portal vein to mix and exchange substances

Question 7

What organelles do hepatocytes have and why?

Answer 7

• Nucleus: allows cell to divide
• Golgi apparatus
• Lots of mitochondria: provides ATP as cell is metabolically active

Question 8

What are the three functions of the liver?

Answer 8

• Homeostatic control of blood glucose
• Deamination of excess amino acids
• Detoxification

Question 9

What is happens to the amino acid in deamination?

Answer 9

• Amino group enters Ornithine cycle as ammonia
• Rest of molecule used in respiration or converted into lipids for storage

Question 10

How is urea formed in the ornithine cycle?

Answer 10

Reaction between ammonia and carbon dioxide

Question 11

What is ethanol broken down into, and what is the use of this product?

Answer 11

• Ethanol -> ethanal -> ethanoate
• Ethanoate is use din respiration or lipid synthesis

Question 12

What enzyme breaks down alcohol?

Answer 12

Alcohol dehydrogenase

Question 13

What enzyme breaks down hydrogen peroxide?

Answer 13

Catalase