Study Qstns lecture 22-25

Study Qstns lecture 22-25 -...

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LECTURES 22, 23, 24, and 25: Cardiovascular Structure and Function FACTS 1. Describe VO2 using the Fick principle and identify the equations for both pulmonary (to the lungs and VO2 = Qc x (arterial [O2] – venous [O2]) In general: oxygen consumption = total blood flow (cardiac output) X uptake of O2 from blood by tissue Mean arterial pressure = total cardiac output X total arterial resistance: MAP = Q x Ra Cardiac output = Mean arterial pressure / total arterial resistance 2. What are the general purposes of the cardiovascular system? To support cellular metabolism by delivering metabolic substrates and removing wastes. 3. What are the coronary arteries? The heart supplies itself with blood. 4. Describe the sequence of depolarization in the heart (starting at the sino-atrial node) SA node AV node bundle of His purkinje fibers 5 . Give a brief description of the cardiac cycle, noting the timing of isometric contraction and relaxation, the closing and opening of the atrio-ventricular Vs. aortic valves, and when maximum ejection of blood occurs. 6. In a cardiac pressure-volume loop , what would be the effects of increased preload, afterload or contractility? Preload increases stroke volume which increases cardiac output. Afterload (what heart pushes against) decreases stroke volume which decreases cardiac output. 7. Define stroke volume, cardiac output, and ejection fraction. Stroke volume = end diastolic volume – end systolic volume Cardiac output = HR x SV Ejection fraction = stroke volume/end diastolic volume 8. Overview of the factors affecting Q c during exercise: preload, afterload, contractility, and heart rate. Preload = blood in heart, more = more stretch = more stretch = more pressure = more stroke volume. Afterload = more blood outside = more resistance for blood inside to leave = move work = less stroke volume Contractility = strength of contraction = increases stroke volume Heart rate = less stroke volume, but more overall increase in cardiac output (just not to the same extent) 9. Describe the Frank-Starling curve. Would changes in preload or contractility alter ventricular performance? It keeps increasing but more slowly and slowly with each increase (page 301). Increasing preload and contractility increases ventricular performance. 10. What are the trends in vessel diameter and blood velocity, from the aorta to the capillaries to the vena cava?
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Study Qstns lecture 22-25 -...

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