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21 Cards in this Set
- Front
- Back
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Where does material exchange occur in the lungs? |
In the alveoli |
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How many alveoli are in an average persons lungs? What does this provide along with the their small size? |
Approx 500 million; this provides a high surface area. |
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What is the approximate radius of an aveolus? |
125*10^-6 m |
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Does the diaphragm contract or relax during inhalation and exhalation? |
Relaxes during exhalation Contracts during inhalation |
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What is compliance? |
How much the lung volume changes for a given change in pressure (dV/dP) |
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Does compliance decrease or increase as lung volume increases? |
Decreases |
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What contributes to the work of breathing? |
- Overcoming surface tension forces - Expanding elastic lung tissue - Overcoming resistance to flow in airways |
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Where is surface tension found? What does it do? |
Where the moist inner surface of aveoli comes into contact with air and it resists the expansion of alveoli during breathing |
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What chemical is produced by the body to reduce surface tension? |
Surfactant |
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What controls the elastic properties of the lungs? |
Collagen and elastin |
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What is Poiseulle's law concerning resistance to flow in airways? |
R is proportional to 1/(r^4) |
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What has more effect on breathing; oxygen or carbon dioxide levels in the blood? |
Carbon dioxide levels |
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What is tidal volume? (VT) |
Volume of air inhaled during a single breath |
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What is functional residual capacity? (FRC) |
Volume of air left in the lungs after a normal exhalation |
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What is the equation for FRC? |
(V*(C1-C2))/C2
C is the concentration of gas left before and after inhalation |
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What is anatomic dead space? |
Airways in which no alveoli are present |
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What is alveolar dead space? |
Alveoli that do not get blood supply |
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What is the equation for partial pressure? |
Partial pressure is equal to the product of the volume fraction of the gas in the mixtures and the total pressure of the mixture of gasses PPartial = V1/VT * PT |
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Does blood arriving at the lungs have a low or high partial pressure of oxygen? |
Low |
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Haemoglobin is a protein in blood with a strong affinity for O2. How many O2 molecules can each haemoglobin carry? |
4 |
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Haemoglobin saturation of oxygen depends on what? |
Partial pressure of oxygen |
