Lec 12-Intro to Cardio
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Lec 12-Intro to Cardio

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Questions and Answers

Which of the following is NOT a major component of the circulatory system?

  • Blood vessels
  • Kidneys (correct)
  • Heart
  • Blood

    • What is the purpose of having separate atrial and ventricular syncytia in the heart?

  • To regulate blood flow in the circulatory system
  • To prevent electrical impulses from spreading between the atria and ventricles (correct)
  • To maintain the electrical conduction system of the heart
  • To ensure efficient contraction of the heart

    • Which of the following is the only normal electrical pathway between the atria and the ventricles?

  • Bundle of His
  • Purkinje fibers
  • AV node (correct)
  • SA node

    • Which ion primarily determines the resting membrane potential?

    <p>K+</p> Signup and view all the answers

    Which channel is responsible for hyperpolarization-activated cyclic nucleotide-gated channel?

    <p>HCN channel</p> Signup and view all the answers

    What is the role of the SA node in the heart?

    <p>Generate action potentials</p> Signup and view all the answers

    What is the mechanism that suppresses latent pacemakers from driving the heart rate?

    <p>Overdrive suppression</p> Signup and view all the answers

    Which component of the circulatory system carries oxygenated blood away from the heart to tissues?

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

    What is the primary function of the cardiovascular system?

    <p>All of the above</p> Signup and view all the answers

    What is the total flow of blood out of the left ventricle known as?

    <p>Cardiac output (CO)</p> Signup and view all the answers

    Which type of cardiac muscle cells do not contribute to the generation of force for pumping blood?

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

    Which type of current is responsible for repolarization in phase 3 of the action potential?

    <p>Outward IK</p> Signup and view all the answers

    What is the main effect of sympathetic nerves on heart rate?

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

    What is the effect of parasympathetic nerves on heart rate?

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

    During which phase of the action potential are most Na+ channels closed?

    <p>Phase 1</p> Signup and view all the answers

    Which part of the heart has the fastest conduction velocity?

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

    Which part of the heart has the slowest conduction velocity?

    <p>AV node</p> Signup and view all the answers

    What is the purpose of the slow conduction velocity in the AV node?

    <p>To prevent early activation of ventricles</p> Signup and view all the answers

    What is the purpose of the rapid conduction velocity in the Purkinje fibers?

    <p>To ensure efficient ejection of blood</p> Signup and view all the answers

    Which receptor is coupled to GK that inhibits adenylyl cyclase?

    <p>M2 receptors</p> Signup and view all the answers

    What effect does parasympathetic nerve activation have on heart rate?

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

    What causes the negative shift in the maximum diastolic potential in SA nodal cells during parasympathetic nerve activation?

    <p>Increase in IK-ACh</p> Signup and view all the answers

    What does the PR interval on an ECG represent?

    <p>Conduction time from atria to ventricles</p> Signup and view all the answers

    Which receptor is coupled to GK that inhibits adenylyl cyclase?

    <p>M2 receptor</p> Signup and view all the answers

    What effect does parasympathetic nerve activation have on heart rate?

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

    What is the effect of sympathetic nervous system on conduction velocity through the AV node?

    <p>Increases conduction velocity</p> Signup and view all the answers

    What does the PR interval on an ECG represent?

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

    Which ion is responsible for the upstroke of the action potential in SA cells?

    <p>Na+</p> Signup and view all the answers

    What is the role of HCN channels in the SA node?

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

    What is the mechanism that suppresses latent pacemakers from driving the heart rate called?

    <p>Overdrive suppression</p> Signup and view all the answers

    Which part of the heart is responsible for generating action potentials spontaneously?

    <p>SA node</p> Signup and view all the answers

    What is the main function of conducting cells in the heart?

    <p>Carry electrical signals rapidly</p> Signup and view all the answers

    Which syncytium in the heart works as a coordinated unit to pump blood?

    <p>Both atrial and ventricular syncytia</p> Signup and view all the answers

    What is the purpose of the AV node in the heart?

    <p>Slow down the conduction velocity</p> Signup and view all the answers

    During which phase of the action potential are most Na+ channels closed?

    <p>Phase 1</p> Signup and view all the answers

    What is the effect of sympathetic nerves on heart rate?

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

    What is the effect of parasympathetic nerves on heart rate?

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

    Which receptor is coupled to GK that inhibits adenylyl cyclase?

    <p>Muscarinic M2 receptor</p> Signup and view all the answers

    Which part of the heart has the slowest conduction velocity?

    <p>AV node</p> Signup and view all the answers

    What is the purpose of the slow conduction velocity in the AV node?

    <p>To delay the conduction of action potential</p> Signup and view all the answers

    What is the purpose of having separate atrial and ventricular syncytia in the heart?

    <p>To allow for smooth sequence of ventricular activation</p> Signup and view all the answers

    What is the effect of sympathetic nervous system on conduction velocity through the AV node?

    <p>Increases conduction velocity</p> Signup and view all the answers

    Which of the following is true about M2 receptors?

    <p>They inhibit adenylyl cyclase</p> Signup and view all the answers

    What effect does sympathetic nervous system have on conduction velocity through the AV node?

    <p>It increases conduction velocity</p> Signup and view all the answers

    What does the QT interval on an ECG represent?

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

    Which of the following is NOT a cause of sinus tachycardia?

    <p>Parasympathetic nerve activation</p> Signup and view all the answers

    Which of the following is the correct sequence of cardiac activation (depolarization) starting from the SA node?

    <p>SA node - AV node - bundle of His - Purkinje fibers</p> Signup and view all the answers

    Which of the following is responsible for lengthening the absolute refractory period in contractile cell action potentials?

    <p>L-type Ca2+</p> Signup and view all the answers

    What are the major features of an ECG and what do they correspond to in the heart?

    <p>P wave - atrial depolarization, QRS wave - ventricular depolarization, S-T segment - ventricular repolarization, T wave - atrial repolarization</p> Signup and view all the answers

    Which of the following is responsible for the upstroke of the action potential in contractile cells?

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

    Which of the following best describes the role of the AV node in the heart?

    <p>It conducts electrical signals from the atria to the ventricles.</p> Signup and view all the answers

    Which of the following is NOT a major component of the circulatory system?

    <p>Lymph nodes</p> Signup and view all the answers

    Which phase of the action potential is characterized by repolarization?

    <p>Phase 3</p> Signup and view all the answers

    What is the effect of sympathetic nervous system on heart rate?

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

    Which ion primarily determines the resting membrane potential?

    <p>K+</p> Signup and view all the answers

    What is the role of HCN channels in the SA node?

    <p>They increase the rate of spontaneous depolarization</p> Signup and view all the answers

    Which of the following is responsible for generating action potentials spontaneously in the heart?

    <p>Sinoatrial node</p> Signup and view all the answers

    Which part of the heart has the fastest conduction velocity?

    <p>Sinoatrial (SA) node</p> Signup and view all the answers

    What is the main function of the conducting cells in the heart?

    <p>To carry electrical signals rapidly</p> Signup and view all the answers

    What is the effect of parasympathetic nerve activation on heart rate?

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

    Which ion primarily determines the resting membrane potential?

    <p>K+</p> Signup and view all the answers

    What is the purpose of the slow conduction velocity in the AV node?

    <p>To prevent rapid transmission of electrical signals to the ventricles</p> Signup and view all the answers

    What is the effect of parasympathetic nerves on heart rate?

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

    What is the role of HCN channels in the SA node?

    <p>To generate action potentials</p> Signup and view all the answers

    Which part of the specialized conduction system has the fastest conduction velocity?

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

    What is the purpose of the slow conduction velocity in the AV node?

    <p>To allow time for ventricles to fill with blood from atria</p> Signup and view all the answers

    What is the main function of the specialized conduction system in the heart?

    <p>To coordinate the pumping of blood</p> Signup and view all the answers

    What is the effect of sympathetic nervous system on conduction velocity through the AV node?

    <p>Increases conduction velocity</p> Signup and view all the answers

    Which of the following is true about M2 receptors?

    <p>M2 receptors are coupled to GK that inhibits adenylyl cyclase</p> Signup and view all the answers

    What does the PR interval on an ECG represent?

    <p>Time from initial depolarization of the atria to initial depolarization of the ventricles</p> Signup and view all the answers

    What effect does parasympathetic nerve activation have on heart rate?

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

    What is the purpose of the slow conduction velocity in the AV node?

    <p>To delay the transmission of electrical signals from atria to ventricles</p> Signup and view all the answers

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