Control of The Heart Quiz
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Questions and Answers

Which equation represents the relationship between mean arterial pressure (MAP), cardiac output, and total peripheral resistance?

  • MAP = cardiac output / total peripheral resistance
  • MAP = cardiac output - total peripheral resistance
  • MAP = cardiac output + total peripheral resistance
  • MAP = cardiac output × total peripheral resistance (correct)

What is the formula to calculate cardiac output?

  • Cardiac output = heart rate / stroke volume
  • Cardiac output = heart rate - stroke volume
  • Cardiac output = heart rate × stroke volume (correct)
  • Cardiac output = heart rate + stroke volume

Which of the following statements accurately describes stroke volume (SV)?

  • It is the volume of blood pumped out of each ventricle per heartbeat. (correct)
  • It is the volume of blood found in each atrium at the end of diastole.
  • It is the volume of blood left in each ventricle at the end of systole.
  • It is the volume of blood that fills the atria during relaxation.

What is the formula to calculate stroke volume (SV)?

<p>SV = EDV - ESV (A)</p> Signup and view all the answers

When does the end systolic volume (ESV) occur?

<p>At the end of systole (D)</p> Signup and view all the answers

What does a decrease in ejection fraction indicate?

<p>A decrease in systolic function (B)</p> Signup and view all the answers

What is ejection fraction?

<p>The ratio of stroke volume to total volume in the ventricle (A)</p> Signup and view all the answers

What happens during diastolic heart failure?

<p>A decrease in both stroke volume and total volume (A)</p> Signup and view all the answers

Which of the following factors promotes venous return to the heart?

<p>Skeletal muscle contraction (A)</p> Signup and view all the answers

What effect does inhalation have on venous return?

<p>Decreases intrathoracic pressure (B)</p> Signup and view all the answers

How does gravity affect venous return?

<p>Decreases venous return by pooling blood in the limbs (C)</p> Signup and view all the answers

Which of the following represents the relationship described by Starling's law of the heart?

<p>Increased EDV causes an increased force of contraction. (C)</p> Signup and view all the answers

What is the role of sarcomere stretching in relation to Starling's law of the heart?

<p>Sarcomere stretching generates a more forceful contraction. (D)</p> Signup and view all the answers

What is the effect of increasing end-diastolic volume (EDV) on the force of contraction in the heart?

<p>Increase in EDV leads to an increase in the force of contraction. (C)</p> Signup and view all the answers

What is the relationship between venous return (VR) and end-diastolic volume (EDV)?

<p>Increase in VR leads to an increase in EDV (C)</p> Signup and view all the answers

What effect does an increase in stroke volume (SV) have on cardiac output (CO)?

<p>Increase in SV leads to an increase in CO (A)</p> Signup and view all the answers

What is the role of calcium in excitation-contraction coupling in cardiomyocytes?

<p>Calcium binds to troponin C (D)</p> Signup and view all the answers

What is the role of calcium in excitation-contraction coupling in cardiomyocytes?

<p>Calcium enhances the affinity of troponin C for actin during contraction. (C)</p> Signup and view all the answers

What effect does stretching the heart muscles have on the force of contraction?

<p>Increases the affinity of troponin C towards calcium ions (A)</p> Signup and view all the answers

What is the significance of Starling's law in relation to contraction force?

<p>It increases the force of contraction (B)</p> Signup and view all the answers

Which of the following events occurs after calcium enters during excitation-contraction coupling in cardiomyocytes?

<p>Calcium-induced calcium release via the sarcoplasmic reticulum (SR). (C)</p> Signup and view all the answers

Which of the following mechanisms is responsible for positive inotropy observed after an increase in heart rate?

<p>Bowditch effect (B)</p> Signup and view all the answers

What is the role of the Na+/K+-ATPase in maintaining the Na+ gradient in cardiomyocytes?

<p>It pumps Na+ out of the cell and K+ into the cell. (D)</p> Signup and view all the answers

What effect does the Anrep effect have on myocardial contractility?

<p>Positive inotropy (D)</p> Signup and view all the answers

What is the main function of SERCA in cardiomyocytes?

<p>To pump Ca2+ into the SR from the sarcoplasm (D)</p> Signup and view all the answers

What is the role of troponin in the mechanism of inotropy in cardiomyocytes?

<p>To bind Ca2+ and induce the release of Ca2+ from the SR (A)</p> Signup and view all the answers

Which of the following statements accurately describes the Bowditch effect?

<p>Increase in heart rate will increase the contractility of the heart (A)</p> Signup and view all the answers

What happens to starlings law when heart rate increases?

<p>It cannot be fully triggered (A)</p> Signup and view all the answers

What happens to contractility in a failing heart when heart rate increases?

<p>It decreases (A)</p> Signup and view all the answers

Which of the following is the main mechanism responsible for the Anrep effect in cardiomyocytes?

<p>Accumulation of Ca2+ sets the myocardium to contract more readily and forcefully. (D)</p> Signup and view all the answers

What is the role of the Na+/K+-ATPase in the Anrep effect?

<p>It maintains the Na+ gradient in cardiomyocytes. (D)</p> Signup and view all the answers

How does the Anrep effect affect the force of myocardial contraction?

<p>It increases the force of myocardial contraction. (B)</p> Signup and view all the answers

What is the primary focus of Starling's law of the heart?

<p>Balancing preload and cardiac output. (C)</p> Signup and view all the answers

What is the primary focus of the Anrep effect?

<p>Balancing afterload and cardiac output. (B)</p> Signup and view all the answers

Which of the following equations represents the relationship between cardiac output (CO), stroke volume (SV), and heart rate (HR)?

<p>CO = SV x HR (A)</p> Signup and view all the answers

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