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26 Cards in this Set
- Front
- Back
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Compare arterial thickness between systemic arteries/arterioles with pulmonary arteries.
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Pulmonary arteries are thinner
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True/False Pulmonary arteries are more like systemic veins in wall thickness and composition.
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TRUE
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Compare musculature in the walls of pulmonary arteries/arterioles with systemic arteries and arterioles.
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Pulmonary arteries/arterioles have a distinct lack of muscles.
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True/False Pulmonary capillaries are like systemic capillaries having only one layer of endothelium.
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TRUE
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Compare pulmonary arteries with systemic arteries in terms of length?
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Pulmonary arteries are shorter
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Compare pulmonary arterial pressure with systemic circulation.
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Pulmonary arterial pressures are about 1/5 of the systemic circulation
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Give approximate values for pulmonary systolic, diastolic and mean pressures.
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Systolic: 25 mmHg Diastolic: 10 mmHg Mean: 15 mmHg
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Give an approximate value for the pulmonary venous pressure.
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5-10 mmHg
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Is left atrial pressure greater or smaller than pulmonary venous pressure?
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Smaller (otherwise no pressure gradient and thus no flow)
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What is a resistance unit?
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1 mmHg/(L/min)
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Compare resistance of the systemic circulation with that of the pulmonary circulation.
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19.5 mmHg/(L/min) vs. 2 R.U.s
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Where is much of the vascular resistance in the lungs found (very different from systemic circulation)?
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In the venous portion of the pulmonary circulation
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Explain why gravity exerts effects on pulmonary pressure.
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The top of the lung can be 20 cm above the pulmonary artery. It will then require an add'l 15 mmHg to get to the apex of the lung. The bottom of the lung is 10 cm below the heart, consquently, the lower portion of the lung receives more flow than the upper.
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In a tall man, with normal pulmonary artery pressures, blood may flow through the top portion of the lung only during systole when pressure exceeds ___ mmHg.
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15
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What happens to the apices of the lungs when the pulmonary arterial pressure is lower than the force of gravity?
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No blood flow occurs
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What are the three lung zones?
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Zone 1, Zone 2, and Zone 3
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What zone? An area of the lung where alveolar pressure exceeds pulmonary artery pressure during entire cardiac cycle. If this situation occurs there is no flow.
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Zone 1
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What zone? An area of the lung where the alveolar pressure exceeds the mean (but not systolic) pulmonary arterial pressure which exceeds the pulmonary ventricular pressure.
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Zone 2
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In which lung zone does pulsatile blood flow occur?
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Zone 2 (The blood flows in systole and ceases in diastole because it is dependent on pulse pressure)
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What zone? Where Pulmonary artery pressure is greater than Pulmonary venous (or ventricular) pressure which greater than alveolar pressure?
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Zone 3
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Which zone is characterized by continuous flow throughout systole and diastole?
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Zone 3
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How does hypoxia effect the pulmonary vascular resistance?
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Unlike in the systemic circulation, a decrease in Oxygen results in the constriction of pulmonary blood vessels increasing vascular resistance.
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Differentiate between segmental and diffuse hypoxia.
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Segmental hypoxia occurs when a portion of the lungs is damaged, blood is redirected to better oxygenated areas. In a diffuse hypoxic event such as altitude the whole system constricts resulting in total reduced oxygenation.
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What is the effect of underinflation or overinflation of the lungs on pulmonary circulation resistance?
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Increases the pulmonary resistance to circulation
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How does recruitment of capillaries affect pulmonary vascular resistance?
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It decreases it (via the increased number of parallel pathways)
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Give another name for atelectasis.
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Collapsed lung
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