Cardiac 1.1
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Questions and Answers

What is the major variable controlling resistance in a tube, as per Poiseuille’s Law?

  • Fluid viscosity
  • Inside radius of the tube (correct)
  • Length of the tube
  • Pressure differential

    • How does blood viscosity change with temperature?

  • Decreases with cooler temperatures
  • Remains constant with temperature changes
  • Increases with cooler temperatures (correct)
  • Is not affected by temperature

    • According to Poiseuille’s Law, how does the flow rate of liquid through a capillary tube change with the radius of the tube?

  • Unaffected by the radius of the tube
  • Proportional to the square of the radius of the tube
  • Inversely proportional to the radius of the tube
  • Directly proportional to the radius of the tube (correct)

    • What factor has the greatest quantitative and physiological effect on resistance in the body?

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

    What clinical application demonstrates the dominant influence of vessel radius on resistance and flow?

    <p>Determination of vascular dilation in response to pharmacologic agents</p> Signup and view all the answers

    How does an increase in blood viscosity affect resistance according to Poiseuille’s Law?

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

    What changes in the body affect pressure and flow due to their influence on vessel radius?

    <p>Changes in heart valve orifice size</p> Signup and view all the answers

    Which factor determines blood viscosity?

    <p>Hematocrit (Hct) and body temperature</p> Signup and view all the answers

    What happens to resistance when vessel diameter changes due to contraction and relaxation of vascular smooth muscle?

    <p>Resistance decreases exponentially</p> Signup and view all the answers

    What clinical application demonstrates the effect of changes in vascular tone and pathology on pressure and flow?

    <p>Vascular stenosis</p> Signup and view all the answers

    Which of the following components are included in the circulatory system overview?

    <p>Coronary Perfusion/Myocardial Oxygen Balance and Cardiac Performance</p> Signup and view all the answers

    What is the leading cause of death for men, women, and people of most racial and ethnic groups in the U.S.?

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

    How often does a person die in the U.S. due to CAD?

    <p>Every 30 seconds</p> Signup and view all the answers

    What is the approximate annual cost of CAD to the U.S.?

    <p>$240 billion</p> Signup and view all the answers

    What percentage of adults age 20 and older have CAD in the U.S.?

    <p>5%</p> Signup and view all the answers

    In 2021, what percentage of deaths from CAD occurred in adults under 65 years old in the U.S.?

    <p>20%</p> Signup and view all the answers

    Which valve directs deoxygenated blood from the right ventricle into the pulmonary artery?

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

    What is the primary function of the left heart?

    <p>To pump blood to the body</p> Signup and view all the answers

    What is the common wall between the atria of the heart called?

    <p>Interatrial septum</p> Signup and view all the answers

    Which structure is formed mainly by the left atrium at the level of the 3rd costal cartilage?

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

    What is the primary function of the right heart?

    <p>To pump blood to the lungs</p> Signup and view all the answers

    What prevents eversion of the mitral valve during ventricular systole?

    <p>Chordae tendinae</p> Signup and view all the answers

    What lies slightly to the left of the midline and has a broad superior portion to include origin of major blood vessels?

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

    What is primarily responsible for pushing blood through the systemic circuit?

    <p>Left ventricle</p> Signup and view all the answers

    What is located at orifice of coronary sinus and may prevent regurgitation of blood into coronary sinus during contraction of atrium?

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

    Which chamber does not care about oxygenated blood from lungs?

    <p>Right ventricle</p> Signup and view all the answers

    What directs incoming oxygenated blood from inferior vena cava to foramen ovale and away from right atrium in fetus?

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

    What should be considered as a pump during atrial systole and provides 20-30% increase in LVEDV?

    <p>Left atrium</p> Signup and view all the answers

    What is the major determinant of coronary perfusion pressure (CPP) under normal conditions?

    <p>Left ventricular end-diastolic pressure (LVEDP)</p> Signup and view all the answers

    Which valve has symptoms when the surface area is decreased by half?

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

    In the context of myocardial supply and demand, which factor affects oxygen supply?

    <p>Arterial oxygen tension</p> Signup and view all the answers

    What is the formula to calculate arterial oxygen content (CaO2)?

    <p>(SaO2 x Hgb X 1.34) + (0.003 x PaO2)</p> Signup and view all the answers

    Which factor decreases coronary perfusion pressure?

    <p>Increased left ventricular end-diastolic pressure (LVEDP)</p> Signup and view all the answers

    What decreases coronary perfusion pressure according to the given text?

    <p>Increases in LVEDP</p> Signup and view all the answers

    What is the normal area of the pulmonic valve?

    <p>2.5–4.0 cm2</p> Signup and view all the answers

    Which condition increases myocardial O2 consumption?

    <p>Decreased diastolic filling time</p> Signup and view all the answers

    What is the formula for calculating arterial oxygen content (CaO2) given in the text?

    <p>(SaO2 x Hgb X 1.34) + (0.003 x PaO2)</p> Signup and view all the answers

    What is the ratio used to determine O2 supply to O2 demand according to the text?

    <p>Myocardial Oxygen Balance</p> Signup and view all the answers

    Which artery supplies most of the right ventricle and the posterior part of the left ventricle in 80-90% of people?

    <p>Right coronary artery</p> Signup and view all the answers

    What is the primary branch of the right coronary artery that supplies the inferior aspect of the heart?

    <p>Right posterior descending artery</p> Signup and view all the answers

    Which artery supplies the left side of the heart, including the left ventricle and left atrium?

    <p>Left circumflex artery</p> Signup and view all the answers

    How is cardiac dominance determined based on which coronary artery crosses the junction between the atria and ventricles to supply the posterior descending coronary branch?

    <p>Blood flow in the coronary arteries</p> Signup and view all the answers

    Which vein runs alongside the left anterior descending artery?

    <p>Great cardiac vein</p> Signup and view all the answers

    Where does blood returning from the left ventricle drain into?

    <p>Coronary sinus</p> Signup and view all the answers

    Which part of the heart is primarily affected by changes in V2 – V5 in an EKG, indicating an anterolateral wall myocardial infarction?

    <p>Anterior wall of the left ventricle</p> Signup and view all the answers

    What is the primary cause of a heart attack?

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

    Which component of the circulatory system is responsible for blood flow from the left ventricle through all organs and tissues, except the lungs, and then to the right atrium?

    <p>Systemic circulation</p> Signup and view all the answers

    What is the function of arterioles in the circulatory system?

    <p>Regulating blood-flow distribution to various organs</p> Signup and view all the answers

    What is the primary function of capillaries in the circulatory system?

    <p>Exchanging nutrients, gases, and metabolic end products with tissues</p> Signup and view all the answers

    What is the role of veins in the circulatory system?

    <p>Facilitating blood flow back to the heart</p> Signup and view all the answers

    What is the primary function of plasma in the blood?

    <p>Containment of dissolved proteins, nutrients, ions, and waste products</p> Signup and view all the answers

    According to Ohm's law, what correlates with the flow of electricity and resistance to this flow in the hemodynamic Ohm's Law?

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

    What is applicable to aspects of medicine based on Poiseuille's Law?

    <p>Blood flow</p> Signup and view all the answers

    What does Reynold's number (Re) predict?

    <p>Laminar or turbulent flow</p> Signup and view all the answers

    What does hemodynamic Ohm's Law correlate with as per Poiseuille's Law?

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

    What is directly proportional to the pressure difference between two points and inversely proportional to the resistance in hemodynamics?

    <p>Blood flow</p> Signup and view all the answers

    What does physiological processes within the circulatory system depend on?

    <p>Both chemistry and physics laws</p> Signup and view all the answers

    What is the inherent rate of the SA node in the cardiac conduction system?

    <p>70 – 100 beats per minute</p> Signup and view all the answers

    Where does the impulse originating from the SA node travel to?

    <p>AV node by way of internodal fibers</p> Signup and view all the answers

    What is the primary function of the AV bundle in the cardiac conduction system?

    <p>To transmit impulses from the AV node to the ventricles</p> Signup and view all the answers

    What is the role of T-tubules and sarcoplasmic reticulum in cardiac muscle?

    <p>Maintain Ca++ homeostasis for contraction and relaxation</p> Signup and view all the answers

    What is the overall process by which depolarization of muscle fiber causes Ca+2 release from sarcoplasmic reticulum into myoplasm called?

    <p>Cardiac muscle excitation-contraction coupling</p> Signup and view all the answers

    What prevents actin-myosin interaction in cardiac muscle?

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

    During contraction, what do myosin heads do in cardiac muscle?

    <p>Interact w/ actin filaments, forming cross-bridges and pivot to produce motion</p> Signup and view all the answers

    Which protein binds tropomyosin to G-actin and is controlled by Ca++ in cardiac muscle?

    <ul> <li>Troponin</li> </ul> Signup and view all the answers

    What initiates the shortening of Z lines in cardiac muscle during excitation-contraction coupling?

    <ul> <li>Myosin cross bridges bind to active filament by alternately attaching and detaching from active sites</li> </ul> Signup and view all the answers

    What are the components of thin filaments in cardiac muscle?

    <p>Actin, Troponin, Tropomyosin</p> Signup and view all the answers

    In what cardiac muscle process does myosin bind to actin and use energy to drag actin filaments toward the center of sarcomere?

    <p>Sliding Filament Theory</p> Signup and view all the answers

    What is the primary role of myosin in cardiac muscle during contraction?

    <p>Interact w/ actin filaments, forming cross-bridges and pivot to produce motion</p> Signup and view all the answers

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