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</p> Signup and view all the answers

    When does the end systolic volume (ESV) occur?

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

    What does a decrease in ejection fraction indicate?

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

    What is ejection fraction?

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

    What happens during diastolic heart failure?

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

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

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

    What effect does inhalation have on venous return?

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

    How does gravity affect venous return?

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

    What effect does the Anrep effect have on myocardial contractility?

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

    What happens to starlings law when heart rate increases?

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

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

    <p>It decreases</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.</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.</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.</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.</p> Signup and view all the answers

    What is the primary focus of the Anrep effect?

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

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