Cardiac Metabolism ILOs Quiz

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What is the main effect of fatty acids and ketone bodies on pyruvate dehydrogenase activity?

Have no impact on pyruvate dehydrogenase activity

Activate the conversion of pyruvate to acetyl CoA

Increase the activity of pyruvate dehydrogenase

Inhibit the activity of pyruvate dehydrogenase (correct)

In the context of Randle's Cycle, what happens to glucose uptake in muscle when fatty acid oxidation is intense?

Halts completely

Decreases (correct)

Increases

Remains constant

How is the rate of carbohydrate (pyruvate and lactate) oxidation by the heart related to plasma free fatty acid concentration?

Directly proportional

Only affects lactate oxidation

Inversely proportional (correct)

Has no relation

What effect do high rates of fatty acid oxidation have on the uptake and oxidation of glucose and lactate?

Inhibit their uptake and oxidation Signup and view all the answers

Which enzyme phosphorylates pyruvate dehydrogenase, leading to a decrease in its activity?

PDH kinase Signup and view all the answers

What is the main function of Randle's cycle in cardiac metabolism?

Promote fatty acid oxidation over glucose oxidation Signup and view all the answers

How does insulin affect carbohydrate metabolism in the heart?

Increases glucose uptake in cardiac muscles Signup and view all the answers

Which of the following best describes the role of insulin in fatty acid metabolism in the heart?

Promotes complete oxidation of fatty acids Signup and view all the answers

How do partial FFA oxidation inhibitors impact cardiac metabolism?

Inhibit the complete oxidation of fatty acids Signup and view all the answers

What effect does glucose uptake in cardiac muscles have on heart function?

Allows for calcium uptake into the sarcoplasmic reticulum Signup and view all the answers

How does insulin affect glycogen storage?

Increases glycogen synthase activity Signup and view all the answers

What is the effect of high insulin levels, such as after a meal, on fatty acid uptake and oxidation by the heart?

Decreases fatty acid uptake and oxidation Signup and view all the answers

How does insulin lower circulating free fatty acid levels?

Suppresses fatty acid release from fat cells Signup and view all the answers

What effect does insulin have on glucose and lactate uptake and oxidation in the heart?

Increases glucose and lactate uptake and oxidation Signup and view all the answers

What is the impact of insulin on the release of fatty acid inhibition on PDH?

Increase in glucose and lactate uptake and oxidation Signup and view all the answers

Which fuel source provides the majority of energy to the heart under basal aerobic conditions?

Free fatty acids Signup and view all the answers

What happens to fatty acid oxidation in the heart when plasma free fatty acid concentrations are high?

Fatty acid uptake and oxidation in mitochondria increase Signup and view all the answers

Which of the following is NOT a primary source of carbohydrate fuel for the myocardium?

Ketone bodies Signup and view all the answers

Where is glucose uptake in cardiac muscles regulated by?

Transmembrane glucose gradient and glucose transporters concentration Signup and view all the answers

Which isoform of the glucose transporter family is predominant in the myocardium?

GLUT4 Signup and view all the answers

What effect does an increase in acetyl CoA/CoA and NADH/NAD ratios have on PDH kinase activity?

Activates PDH kinase Signup and view all the answers

How does high rates of fatty acid oxidation impact pyruvate oxidation?

Decrease pyruvate oxidation Signup and view all the answers

Which group of anti-anginal drugs shifts cardiomyocyte metabolism toward carbohydrate utilization?

Partial FFA Oxidation Inhibitors Signup and view all the answers

How does insulin indirectly increase glucose uptake in cardiac muscles?

By enhancing GLUT1 and GLUT4 incorporation into the sarcolemmal membrane Signup and view all the answers

What effect does insulin have on hexokinase enzyme activity in cardiac muscles?

Increases hexokinase activity Signup and view all the answers