Metabolism in Health and Disease

Question 1

what does insulin stimulate?

Answer 1

1. glycogen synthesis
2. uptake of glucose into muscle and adipose tissue
3. glycolysis and hence fatty acid synthesis in liver
4. formation of triglycerides in fat tissue
5. protein synthesis in muscle

Question 2

what is the role of glucagon in the liver?

Answer 2

1. stimulates release of glucose from glycogen

2. stimulates gluconeogenesis but inhibits glucose incorporation into glycogen

Question 3

what is the role of amines (adrenaline and noradrenaline)?

Answer 3

• drive breakdown of glycogen and triglycerides
• glycogenolytic action mainly on muscle (producing glucose-6-P) rather than on liver
• lower glucose uptake by muscle so that fatty acids released by adipose tissue are used for fuel
• increase glucagon secretion and inhibit insulin secretion

Question 4

what is hypoglycaemia?

Answer 4

lowered blood [glucose] (<3 mmol/litre)

Question 5

what is hyperglycaemia?

Answer 5

elevated blood [glucose] (>11 mmol/litre)

Question 6

what tissues can be damaged due to long-term hyperglycaemia?

Answer 6

• blood vessels (polyneuropathy)
• eyes (retinal blood vessels)
• kidneys (urine infection; scarring and swelling in glomeruli leading to appearance of protein in urine)
• cardiovascular disease (largely a result of narrowing blood vessels)