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30 Cards in this Set
- Front
- Back
What vessels store blood during systole to supply continuous flow to capillaries?
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Arteries
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Which vessels help control cardiac output?
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Veins
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What vessels store blood during systole to supply continuous flow to capillaries?
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Arteries
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Which vessels help control cardiac output?
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Veins
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What are the three layers of a vessel?
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Intima
Media Adventitia |
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Why are the walls of the veins thin?
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Very low pressure in the venous system
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Is the pressure in the large veins greater or lesser than the right atrium?
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greater. Fluid will always for from high pressure to low pressure.
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What equations define compliance?
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C = dV/dP
C = D x V |
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What factors alter compliance?
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Volume
Pressure |
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What vessels are the most distensible?
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veins
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How much more distensible are veins than their corresponding arteries?
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8 times
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What is the volume difference of a vein and its corresponding artery?
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Vein has 3 times more volume
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What is the compliance of a vein in relation to its corresponding artery?
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24 times greater
C = D x V C = 8 x 3 |
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Comparing the arterial and venous systems, how will a change in volume effect the pressure? Why?
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Arterial system: dramatic change in the pressure
Venous system: dampened response. No dramatic shift in pressure. Compliance is much higher in the venous system, allowing greater distensibility. |
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Describe delayed compliance.
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A change in volume will cause a spike in the pressure. Delayed compliance allows the vessels to distend and lower the pressure towards normal. Same is true for a loss of pressure.
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Why would blood only flow through the capillaries during diastole?
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Inelastic vessels lack compliance which would allow continuous flow.
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Which are more responsive to sympathetic nerve stimulation, arteries or veins?
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Veins are more responsive to
sympathetic hyperactivity (i.e. during stress, hemorrhage, exercise) than arteries. |
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Where is central venous pressure taken?
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At the right atrium
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What is the central venous pressure?
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The filling pressure of the right heart
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What is the determinant of the preload of the right ventricle and ultimately stroke volume?
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Central Venous Pressure
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How is central venous pressure increased?
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1. Increase in venous volume
2. Decrease in venous compliance |
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What is the first response to increased central venous pressure?
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Increase in the right ventricular stroke volume.
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What is the effect of increased right ventricular stroke volume?
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Increased cardiac output by the right heart and accumulation of blood in the pulmonary vasculature.
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What four cardiac parameters are effected with an increase in blood volume?
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increased mean systemic pressure
increased venous return increased right atrial pressure increased cardiac output |
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What seven factors effect venous return?
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Blood volume
Systemic pressure Venous tone Movement of skeletal muscles Intrapleural pressure Venous valves Suction of relaxed atrium |
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What factors aid the return of blood to the heart?
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Large diameter veins
one-way valves muscle contractions respiration |
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How does a hemorrhage effect central venous pressure?
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From 0 mm Hg normal to -3 to -5 mm Hg
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How does CHF or a massive blood transfusion effect central venous pressure?
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Dramatic increase in CVP.
20-30 mm Hg |
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What does Toricceli's law state?
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Pressure at the surface of a body of water is equal to the atmospheric pressure, but the pressure rises below the surface.
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How is the hydrostatic column of blood interrupted to reduce pressure?
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With one-way valves
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