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34 Cards in this Set
- Front
- Back
Gas exchange in the lungs occurs where?
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air sacs or alveoli
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According to Fick's Law, the transfer of gasses across cell membranes or capillary walls occur by what means?
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simple diffusion
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For gases, the rate of transfer by diffusion is DIRECTLY proportional to the driving force. True or False.
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True
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The surface area available for diffusion is INVERSELY proportional to the thickness of membrane barrier. True or False
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True
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Lung diffusing capacity (DL) can be measured by what gas?
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Carbon monoxide (CO)
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DL decreases because destruction of alveoli results in a decreased surface area for gas exchange...this leads to what disease?
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Emphysema
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DL decreases because the diffusion distance (membrane thickness or interstitial volume) increases...this causes what?
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Fibrosis or pulmonary edema
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DL decreases because the amount of hemoglobin in red blood cells is reduced ...this causes what disease?
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Anemia
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DL increases because additional capillaries are perfused with blood, which increases the surface area for gas exchange...this happens when?
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during exercise
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The diffusion rates of O2 and CO2 depends on the partial pressure differences across what?
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the membrane and the area available for diffusion
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What is tidal volume (TV)?
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the volume inspired or expired with each normal breath
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What is inspiratory reserve volume (IRV)?
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the volume that can be inspired over and above the tidal volume and is also used during exercise
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What is expiratory reserve volume (ERV)?
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volume that can be expired after the expiration of a tidal volume
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What is residual volume (RV)?
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volume that remains in the lungs after a maximal expiration and it can't be measured by spirometry
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What is anatomic dead space?
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volume of the conducting airways and is normally approximately 150 ml
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What is physiologic dead space?
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-Functional measurement
-defined as the volume of the lungs that does not participate in gas exchange -is approximately equal to anatomic dead space in normal lungs |
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What is inspiratory capacity?
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the sum of tidal volume and inspiratory reserve volume (IRV)
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Functional residual capacity (FRC) is the sum of expiratory reserve volume and residual volume. True or False.
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True
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FRC is the volume remaining in the lungs after a tidal volume is expired. True or False.
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True
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What make up lung volumes? (4)
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-Tidal volume (TV)
-Inspiratory reserve volume (IRV) -Expiratory reserve volume (ERV) -Residual Volume (RV) |
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What are the 4 lung capacities?
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-Inspiratory capacity
-Functional residual capacity (FRC) -Vital Capacity (VC) -Total lung capacity (TLC) |
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What is TLC (total lung capacity)?
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sum of all four lung volumes
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What is the sum of tidal volume, IRV, and ERV?
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vital capacity
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What is the volume of air that can be forcibly expired after a maximal inspiration?
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vital capacity
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What is the volume in the lungs after a maximal inspiration?
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total lung capacity (TLC)
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What is the most important muscle for inspiration?
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diaphragm
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When the diaphragm contracts, the abdominal contents are pushed downward, and the ribs are lifted upward and outward, increasing the volume of the thoracic cavity. True or False.
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True
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Muscles of expiration are normally passive or active?
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Passive
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What do abdominal muscles do?
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compress the abdominal cavity, push the diaphragm up, and push air out of the lungs.
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What pulls the ribs downward and inward?
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internal intercostal muscles
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Surface tension of alveoli results from the attractive forces between molecules of liquid lining the alveoli. True or False.
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True
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Surfactant line what?
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alveoli
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What reduces surface tension by disrupting the intermolecular forces between molecules of liquid?
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surfactant
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Surfactant may be present as early as gestational week 24 and is almost always present by gestational week 35. True or False
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True
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