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17 Cards in this Set
- Front
- Back
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Explain flow limitation.
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Substances crossing the alveolar membrane do not react to substances in the blood and reach equilibrium in less time than it takes for blood to traverse the pulmonary capillaries.
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What is another name for flow limitation?
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Perfusion limitation
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How can flow limitation be overcome?
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By increasing blood flow.
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Explain diffusion limitation?
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Substances react with substances in the blood but equilibrium is not reached in the time it takes for blood to traverse the pulmonary capillaries.
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What is the significance of diffusing capacity?
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It measurement permits evaluation of the diffusion properties of alveolar capillary membrane by measuring the rate of gas transfer(conductance) by the respiratory system.
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What factors affect D(l)?
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The diffusion properties of the system(membrane component and the rate of the chemical reaction of the system(blood component)
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How is O2 transported in blood?
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In arterial blood at Po2 95mm/Hg,
PCo2 at 40mm/Hg and Hb 97% saturated. |
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What is the normal O2 tension of arterial blood?
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85-100mm/Hg
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In normal adults, what are hemoglobin molecules composed of?
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Two alpha and beta chains.
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What is heme?
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Complex made up of a porphyrin ring and one atom of ferrous iron
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What is the role of the ferrous iron(Fe2+)?
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Each ferrous iron binds one O2 molecule reversibly.
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What is the significance of the iron in heme?
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It stays in the ferrous state, so that binding to O2 does not result in its oxidation, but rather in its oxygenation.
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How does Hb after the O2 content in blood?
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Increases the amount of O2, that is carried in the blood compared to plasma almost 70 fold.
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What percentage of O2 in arterial blood is carried by Hb?
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98.5%
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define Hg saturation?
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Percent of hemoglobin that is combined with O2.
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What influences the amount of O2 that combines with hemoglobin?
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O2 tension(Po2) or O2 saturation.
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What is the upper limit for O2 tension in the body?
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100mm/Hg
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