Cardiac Muscle Contraction and Conduction Quiz
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Questions and Answers

What is the role of Ca++ channels at 0mV during repolarization?

  • They open
  • They allow for the plateau
  • They close (correct)
  • They bind to troponin

    • Which component of the heart's conduction system would fire the slowest times per minute?

  • Purkinje fibers (correct)
  • AV node
  • SA node
  • Atrioventricular bundle

    • What would be the heart rate range if the AV node was the primary pacemaker without endocrine control?

  • 80 - 100 BPM
  • 30 - 40 BPM
  • 40 - 60 BPM (correct)
  • 15 - 20 BPM

    • How many leads are typically used for recording an ECG or EKG?

    <p>12 leads</p> Signup and view all the answers

    What happens to K+ channels at 0mV during typical repolarization?

    <p>They open</p> Signup and view all the answers

    What is the main function of P wave in an ECG?

    <p>Depolarization of the atria</p> Signup and view all the answers

    Which phase of the cardiac cycle is characterized by the pumping of blood into circulation?

    <p>Ventricular systole</p> Signup and view all the answers

    What is the primary function of an artificial pacemaker in the context of heart function?

    <p>Delivers electrical impulses for effective heart contractions</p> Signup and view all the answers

    During which phase of the cardiac cycle does the end systolic volume (ESV) refer to the amount of blood left in the ventricles after stroke volume is pushed out?

    <p>Ventricular diastole</p> Signup and view all the answers

    What is the significance of the T wave in an ECG?

    <p>Repolarization of the ventricles</p> Signup and view all the answers

    What is the primary purpose of an Automatic External Defibrillator (AED)?

    <p>Corrects fibrillations</p> Signup and view all the answers

    Where is the heart located in the body?

    <p>Between the lungs in the mediastinum</p> Signup and view all the answers

    Which chamber of the heart is responsible for pumping blood out to the body or lungs?

    <p>Ventricles</p> Signup and view all the answers

    Which layer of the heart is most superficial?

    <p>Epicardium</p> Signup and view all the answers

    What is the function of auricles in the heart?

    <p>Collecting and holding blood to empty into the atria</p> Signup and view all the answers

    Which structure separates the parietal and visceral layers of the serous pericardium?

    <p>Pericardial Cavity</p> Signup and view all the answers

    What is the size of a typical heart compared to that of an athlete's heart?

    <p>Athlete's heart is larger</p> Signup and view all the answers

    Which type of cells in the heart initiate an electrical potential at a fixed rate?

    <p>Autorhythmic cells</p> Signup and view all the answers

    What is the purpose of the desmosomes in cardiac muscle cells?

    <p>Stop cells from ripping apart</p> Signup and view all the answers

    Why do semilunar valves make an audible sound as they close?

    <p>They have no muscular attachments</p> Signup and view all the answers

    What is the main function of the Purkinje fibers in the heart?

    <p>Spread the impulse around the ventricles</p> Signup and view all the answers

    Which structure divides the heart into chambers and are physical extensions of myocardium?

    <p>Septum</p> Signup and view all the answers

    What happens when cardiac conductive cells plateau during depolarization?

    <p>Ca++ channels open</p> Signup and view all the answers

    What is the role of endothelins released by the endothelium in the heart?

    <p>Regulate growth patterns of cardiac muscle cells</p> Signup and view all the answers

    How do tricuspid and mitral valves close in the heart?

    <p>Due to papillary muscles</p> Signup and view all the answers

    What is the primary function of coronary veins in the circulatory system?

    <p>Return deoxygenated blood back to the right atrium</p> Signup and view all the answers

    Which heart sound is associated with the closing of the semilunar valves?

    <p>S2</p> Signup and view all the answers

    What is the normal range for Cardiac Output (CO) in liters per minute?

    <p>4 - 8 L/min</p> Signup and view all the answers

    What is the formula to calculate Cardiac Output (CO)?

    <p>CO = HR * SV</p> Signup and view all the answers

    Which factor increases Heart Rate (HR) through sympathetic stimulation?

    <p>Norepinephrine release</p> Signup and view all the answers

    What is the percentage range for a normal Ejection Fraction?

    <p>50% - 70%</p> Signup and view all the answers

    Which reflex is triggered by increased blood in the atria resulting in a sympathetic response to increase heart rate?

    <p>Atrial reflex</p> Signup and view all the answers

    How can caffeine and nicotine affect Heart Rate?

    <p>Increase it</p> Signup and view all the answers

    Which electrolyte alteration can decrease Heart Rate?

    <p>Alkalosis (too few hydrogen ions)</p> Signup and view all the answers

    What happens if there is little time for blood to fill during increased Heart Rate?

    <p>(ESV) End-Systolic Volume decreases</p> Signup and view all the answers

    Which event occurs before other heart sounds when blood is being pushed into a stiff ventricle?

    <p>S4 sound</p> Signup and view all the answers

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