Understanding Resistance and Flow in Vascular Circuits
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Questions and Answers

Which structure in the heart acts as the natural pacemaker and initiates the electrical impulses that cause the heart to beat?

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

    • Which nervous system increases heart rate by releasing norepinephrine?

  • Sympathetic nervous system (correct)
  • Central nervous system
  • Autonomic nervous system
  • Parasympathetic nervous system

    • Which hormone released by the adrenal glands increases heart rate?

  • Norepinephrine
  • Insulin
  • Acetylcholine
  • Epinephrine (correct)

    • Which ions cause the initiation of action potentials in the heart?

    <p>Calcium ions</p> Signup and view all the answers

    Which of the following is a characteristic of atrial fibrillation (AFib)?

    <p>Decreased efficiency of heart pumping</p> Signup and view all the answers

    What is the equation that describes the relationship between pressure gradient, flow rate, and resistance in a cylindrical vessel?

    <p>Hagen-Poiseuille equation</p> Signup and view all the answers

    Which of the following is true about laminar flow?

    <p>Fluid moves in parallel layers</p> Signup and view all the answers

    What is the most likely cause of ventricular fibrillation (VFib)?

    <p>Ischemic damage</p> Signup and view all the answers

    Which one of the following is the primary pacemaker of the heart?

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

    Which one of the following is responsible for conducting the electrical impulses from the AV node to the ventricles?

    <p>Bundle of His</p> Signup and view all the answers

    Which one of the following cells spreads the electrical impulses throughout the ventricles?

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

    Which one of the following is responsible for initiating each heartbeat and setting the heart rate?

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

    Which of the following structures is responsible for generating and conducting electrical impulses throughout the heart?

    <p>Conduction system</p> Signup and view all the answers

    During which phase of the cardiac muscle action potential does rapid depolarization occur?

    <p>Phase 0</p> Signup and view all the answers

    Which of the following is true about the absolute refractory period in the cardiac muscle action potential?

    <p>It is the period during which the cardiac muscle cell cannot be stimulated to depolarize again, no matter how strong the stimulus is.</p> Signup and view all the answers

    During which phase of the cardiac cycle do the ventricles contract and push blood out of the heart?

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

    According to the text, what is the relationship between resistance and flow in a circuit?

    <p>Resistance and flow have an inverse relationship.</p> Signup and view all the answers

    What is the relationship between conductance and resistance?

    <p>Conductance is the reciprocal of resistance.</p> Signup and view all the answers

    According to the text, how does the diameter of a vessel affect conductance?

    <p>As the diameter increases, conductance increases.</p> Signup and view all the answers

    What is the advantage of vascular compliance?

    <p>Vascular compliance reduces pressure pulsations.</p> Signup and view all the answers

    Which factors regulate right atrial pressure?

    <p>The ability of the heart to pump blood out of the right atrium and ventricle into the lungs</p> Signup and view all the answers

    What can increase right atrial pressure?

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

    What are Korotkoff's sounds?

    <p>Sounds produced by the turbulent flow of blood through the compressed artery</p> Signup and view all the answers

    Which factors determine hemodynamics according to Poiseuille's law?

    <p>Vessel radius</p> Signup and view all the answers

    How is blood flow related to vessel radius according to Poiseuille's law?

    <p>Blood flow is directly proportional to the fourth power of the vessel radius</p> Signup and view all the answers

    Which of the following is NOT a factor that can increase right atrial pressure?

    <p>Decreased blood viscosity</p> Signup and view all the answers

    Which of the following is responsible for contracting to make the heart beat?

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

    Which of the following describes the electrical activity of the SA node over time?

    <p>The graph stops dropping after the K channels close.</p> Signup and view all the answers

    Which of the following is true about the delay at the AV node and Bundle?

    <p>The electrical impulse travels down the bundle of His, a specialized group of cells that conduct the impulse slowly through the ventricular septum.</p> Signup and view all the answers

    Which of the following is true about normal and ectopic pacemakers?

    <p>The normal pacemaker of the heart is the SA node, which generates electrical impulses that cause the heart to beat.</p> Signup and view all the answers

    True or false: Right atrial pressure is regulated solely by the ability of the heart to pump blood out of the right atrium and ventricle into the lungs.

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

    True or false: Increased blood volume can increase the right atrial pressure.

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

    True or false: Dilation of the arterioles allows rapid flow of blood from the veins into the arteries.

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

    True or false: Korotkoff's sounds are produced by the smooth flow of blood through the compressed artery.

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

    True or false: According to Poiseuille's law, blood flow is inversely proportional to the fourth power of the vessel radius.

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

    True or false: The pressure gradient driving blood flow is determined by the difference in pressure between the peripheral veins and the right atrium.

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

    True or false: Vessel length has a direct effect on blood flow according to Poiseuille's law.

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

    True or false: Blood viscosity is one of the physical properties that determine hemodynamics.

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

    True or false: Increased large vessel tone can increase the right atrial pressure.

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

    True or false: According to Poiseuille's law, blood flow is directly proportional to the fourth power of the vessel radius.

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

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