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23 Cards in this Set
- Front
- Back
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What mm control inspiration
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The diaphragm and the external intercostal mm
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What cells produce surfactant
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Alveolar Type II cells
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How much pressure does it take to move a full breath of air in and out of the lungs
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1 mm Hg
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What role does surfactant play in the lungs
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Maintains a negative presure
Decrease surface tension |
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What is tidal volume
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TV = air inhaled or exhaled w/each breath under resting conditions (~500 mL)
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What is inspiratory reserve volume?
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(~3100 mL) amount of air that can be forcefully inhaled after normal TV inhalation
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What is expiratory reserve volume
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(~1200 mL) amount of air that can be forcefully exhaled after a normal TV exhalation
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What is residual volume
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(~1200 mL) amount of air remaining after a forced exhaltion
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What is total lung capacity
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(TLC= ~ 6000 mL) max amount of air contained in lungs after max inspiratory effort. TLC=TV+IRV+ERV+RV
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Forced Vital Capacity
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maximum amount of air that can be expired after a normal inspiratory effort: FVC=TV+IRV+ERV Used in dx of many lung disorders. Goes down in fibrotic condtions
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Dead space
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Anatomical (~150 mL) airways that don't participate in gas exchange
Physiological - anatomical + alveolar that doesn't participate in gas exchange |
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TImed Forced Expiratory Volume (FEV)
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(3800 mL) Max vol of air forcible exhaled in 1 sec. (should be about 80% of FVC) Low in obstructive dz
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Where does voluntary control of respiration begin
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In the cerebral cortex
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Where does automatic control of respiration begin?
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Lower brain centers - pons and medulla
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Peripheral Chemoreceptor control of respiration
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Aortic (arch) and carotid bodies (bifurcation) detect low O2
Plasma H+ ion receptors - detect plasma H+ Both increase ventilation |
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Central Chemoreceptor controls of respiration
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Ventral surface of the medulla (bathed in CSF) Increase in CO2 in CSF leads to increase in H+ --> increases ventilation
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How does Hb buffer H+ in blood
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H+ + HbO2 --> HHb + O2 driving O2 off Hb at tissue
HCO3 + H+ --> H2 CO3 --> CO2 + H2O driving CO2 off Bicarb at lungs |
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What is the ventilation-perfusion ratio
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at apex - lungs are under perfused due to gravity/ at base overperfused for same reason
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What is a physiological shunt in the lungs?
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At apex alveolar P> pulm arterial P --> pulmonary capilaries collapse
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What factors favor O2 offloading (shift to the R)
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Heat, CO2/inc H+/low pH, DPG (high altitude)
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What favors "onloading" (shift to the L)
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High O2 (this takes place in the lungs)
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How is CO2 transported in the blood and what % uses each form of transport
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9% - dissolved in blood
27% - combines w/Hb 64% - combines with H+ to make bicarb (HCO3) |
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What are causes of pulmonary edema
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L heart failure, MI complication,
"leaky" mitral or aortic vlaves, CHF, cardiomyopathies, toxic damage to the lungs |
