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11 Cards in this Set
- Front
- Back
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Which circulation in the lung receives 99% of CO? What is the pulmonary a capillary volume equal to?
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The pulmonary circulation
Stroke volume |
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What is pulmonary wedge pressure?
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An indirect measure of pulmonary veinous pressure that reflects L. atrial pressure.
measure using a Swan-Ganz |
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As lung volume increases, what happens to vascular resistance of alveolar and extra-alveolar vessels? What about total resistance?
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Alveolar vessels increase in resistance.
Extraalveolar vessels DEcrease in resistance. Total R is biphasic, with R falling at lung volumes <70 and R rising >70. |
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Of the four zones in the lung, where is arterial pressure the greatest?
What is flow dependent on in zone 3? |
Alveolar: Zones 2 and 3.
The arterial-venous difference in pressure. Distending the capillaries will increase blood flow. |
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What is the effect of inc. Pco2 and and drop in pH on the pulmonary vasculature?
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Vasoconstriction. (opposite from systemic)
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And increase in pulmonary arterial pressure results in what kind of change in pulmonary vascular resistance?
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Decrease in resistance because more capillaries are opened.
(with exercise) |
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Vasodilate or constrict?
inc. alveolar PO2 dec. alveolar CO2 |
Dilate
This it the opposite effect from the systemic. |
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List some factors that vasodilate pulmonary vascular endothelium
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acetylcholine
histimaine - H2 Protscycling B-adrenergic agonists Bradykinin Nitric oxide |
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Vasodilate or constrict?
dec. alveolar PO2 inc. alveolar PCO2 |
Constrict
Opposite effect from systemic. |
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What is hypoxic vasoconstriction?
What pulmonary disease can it lead to? |
A response of vascular smooth muscle to alveolar PO2 < 70 mmHg to direct blood flow away from poorly ventilated regions.
Pulmonary HTN |
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Due to Starling's forces, what direction of water flow is favored in the lungs?
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Filtration is favored, unless there is excess water in lung. Then, low pressure in perivascular space favors drainage.
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