lecture 11 - cardiac metabolism

Question 1

What types of fuels can the heart not utilise at all?

Answer 1

None - they can utilise all fuel types if completely necessary

Question 2

What is the fuel preference of the myocardium?

Answer 2

Fatty acids - because it is highly oxidative

Question 3

How is the majority of energy produced in the fasting heart?

Answer 3

Mitochondrial respiration

Question 4

In a fasting state, what happens to the balance of carbohydrate and lipid fuel use in the heart?

Answer 4

Increased use of lipids, reduced use of carbohydrates

Question 5

In a hypoxic/exercise state, what happens to the balance of carbohydrate and lipid fuel use in the heart?

Answer 5

Increased carbohydrate use, decreased lipid use

Question 6

What are the 4 factors that modulate fuel utilisation in the heart?

Answer 6

Substrate availability, hormones (insulin, glucagon), oxygen availability, workload/exercise

Question 7

What is the effect on cardiac metabolic substrate use in diabetes?

Answer 7

Increased reliance on Fatty Acids, as carbohydrates cannot be utilised

Question 8

What is the effect on cardiac metabolic substrate use in a hypertrophied heart?

Answer 8

Decreased fatty acid oxidation and increased anaerobic glycolysis with carbohydrates, because the hypertrophied tissue cannot get sufficient oxygen

Question 9

What is the effect on cardiac metabolic substrate use in an ischaemic or hypoxic heart?

Answer 9

Decreased oxidative metabolism, increase glycolysis

Question 10

Which transcription factor is involved in upregualting glycolysis during hypoxia in the heart?

Answer 10

HIF1a

Question 11

What are the beneficial effects of exercise-triggered AMPK?

Answer 11

Decreased cholesterol synthesis, increased fat oxidation, etc.