Cardiac Action Potential and Conduction System
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Questions and Answers

What is the role of the atria in the heart?

  • Collect blood and push it into lower chambers (correct)
  • Hold blood and empty into atria
  • Pump blood out to the body or lungs
  • Produce lubricating fluid

    • Which chamber of the heart connects to the pulmonary trunk?

  • Left atrium
  • Left ventricle
  • Right atrium
  • Right ventricle (correct)

    • In which cavity does the heart sit?

  • Cardiac notch
  • Pulmonary cavity
  • Pericardial cavity (correct)
  • Mediastinum

    • What is the size of a typical heart?

    <p>Size of a fist</p> Signup and view all the answers

    Which artery is the only one to carry deoxygenated blood?

    <p>Pulmonary artery</p> Signup and view all the answers

    What is the thickest layer in the heart, containing muscle cells, nerve fibers, and blood vessels?

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

    What happens at 0mV in terms of ion channels?

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

    Which component of the heart's conduction system fires at the lowest rate per minute?

    <p>Purkinje fibers</p> Signup and view all the answers

    What slows down the firing rate of the SA node below its intrinsic rate?

    <p>Endocrine control</p> Signup and view all the answers

    What is the purpose of electrodes placed on the body during an electrocardiogram (ECG)?

    <p>To record electrical signals of the heart</p> Signup and view all the answers

    What effect does Ca++ have on the myosin and actin cross bridge?

    <p>It allows the myosin and actin cross bridge formation</p> Signup and view all the answers

    What is the purpose of AED's in correcting fibrillations?

    <p>Normalize the heart rate</p> Signup and view all the answers

    During which phase of the cardiac cycle do the semilunar valves close?

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

    What is the main function of an artificial pacemaker?

    <p>Ensure effective heart contractions</p> Signup and view all the answers

    Which component of the cardiac cycle involves the pumping of blood into circulation?

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

    What does the T wave in an ECG represent?

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

    How much blood is normally pushed out by the ventricles in one stroke during the cardiac cycle?

    <p>$70-80$ mL</p> Signup and view all the answers

    What causes the second audible sound 'S2' in a healthy heart?

    <p>Closing of semilunar valves</p> Signup and view all the answers

    What does the presence of both S3 and S4 sounds indicate in a cardiac examination?

    <p>S7 condition</p> Signup and view all the answers

    What is the formula for calculating Cardiac Output (CO) in a healthy individual?

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

    What is the normal range for the Ejection Fraction in a cardiac assessment?

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

    How does exercise affect Cardiac Output (CO) in an individual?

    <p>Increases CO</p> Signup and view all the answers

    What is the purpose of determining the target heart rate during exercise?

    <p>To maintain high Cardiac Output</p> Signup and view all the answers

    What is the function of endothelins released by the endothelium?

    <p>Act as strong vasoconstrictors</p> Signup and view all the answers

    Which structure divides the heart into chambers?

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

    What is the major difference between the right atrium and the left atrium?

    <p>Presence of pectinate muscles</p> Signup and view all the answers

    Which valve ensures unidirectional blood flow?

    <p>Pulmonary valve</p> Signup and view all the answers

    During coronary circulation, what is the purpose of anastomosis?

    <p>Provide alternative routes for blood flow</p> Signup and view all the answers

    What is the function of autorhythmicity in cardiac muscle cells?

    <p>Initiate electrical potential at a fixed rate</p> Signup and view all the answers

    What is the role of desmosomes in cardiac muscle cells?

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

    Where is the Sinoatrial (SA) node located?

    <p>Posterior wall of the right atrium</p> Signup and view all the answers

    What happens to cardiac conductive cells during spontaneous depolarization?

    <p>Na+ channels allow a slow influx of ions</p> Signup and view all the answers

    Why do cardiac contractile cells have a long refractory period?

    <p>To allow for proper relaxation and refilling with blood</p> Signup and view all the answers

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