Myocardial Contractility Factors Quiz

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Which factor is the primary controller of cardiac output according to the text?

The Heart Rate

Efficacy of cardiac contractility= Systolic Performance of the Ventricle

The Venous Return (Preload) (correct)

The Arterial Blood Pressure (Afterload)

What is the resistance against which blood is expelled called?

Efficacy of Cardiac Contractility

Venous Return

Afterload (correct)

Preload

Which of the following factors has a direct effect on cardiac output?

Peripheral Circulation Factors

Arterial Blood Pressure

Efficacy of Cardiac Contractility

The Heart Rate (correct)

What does VR stand for in the text?

Venous Return Signup and view all the answers

Which of the following would increase cardiac output if the heart rate remains unchanged?

Increased stroke volume Signup and view all the answers

What does SV depend on according to the text?

Preload, afterload, and myocardial contractility Signup and view all the answers

How does sympathetic stimulation affect myocardial contractility?

Increases the amount of Ca2+ entry into the cell Signup and view all the answers

What effect does parasympathetic stimulation have on myocardial contractility?

Decreases intracellular calcium levels Signup and view all the answers

How does a high heart rate affect contractility according to Bowditch effect?

Causes a small increase in contractility Signup and view all the answers

Which factor contributes to the increased ejection fraction during increased strength of contraction?

Increase in fiber strength without fiber length increase Signup and view all the answers

What contributes to the force-frequency relation known as the Bowditch effect?

Slower Ca2+ entry into the cell than sequestration by sarcoplasmic reticulum Signup and view all the answers

How do circulating catecholamines affect myocardial contractility?

Augment the positive inotropic effect of norepinephrine Signup and view all the answers

What is the role of valves in the veins?

Prevent backflow of blood in the veins Signup and view all the answers

How does arteriolar dilatation affect blood flow?

Decreases resistance to blood flow Signup and view all the answers

What effect does severe capillary dilatation have on circulatory shock?

Leads to pooling of blood in the capillaries Signup and view all the answers

How does the respiratory pump aid venous return?

Dilates thoracic veins and decreases resistance to blood flow Signup and view all the answers

How does sympathetic stimulation affect venous return?

Increases the venous tone and cardiac suction forces Signup and view all the answers

What is the role of venomotor tone in peripheral circulation?

Maintains partial constriction of venules during rest Signup and view all the answers