10. CP Gas Exchange Flashcards Preview

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Flashcards in 10. CP Gas Exchange Deck (9)
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1
Q

What is the average value for perfusion?

A

5L / min

2
Q

What disease can increase the distance factor in the perfusion equation?

What does this do to perfusion?

A

Interstitial lung disease

3
Q

Is the diffusion coefficient for CO2 higher or lower than O2?

A

CO2’s diffusion coefficient is much higher (20x) than that of O2

4
Q

What is the pressure difference between alveolar O2 and the O2 in the capillaries?

A

60 mmHg

5
Q

Why do you see exercise intolerance in lung disease before you see resting hypoxia?

A

Because a given RBC spends exactly as much time in the lungs during exercise as it needs to pick up its full complement of oxygen and no more. Any damage to the perfusion means that the RBC cannot fully absorb O2 in the lungs before returning to the periphery.

6
Q

What is the average diffusion capacity of the lung for oxygen?

A

21ml O2 / min / mmHg at rest

7
Q

What is the correction factor for the diffusion constant of O2 vs that of CO?

A

DLO2 = 1.23 DLCO

8
Q

What is the purpose of surfactant?

How does it account for alveoli of different sizes?

A

Reduces surface tension to prevent collapse of the alveoli

It reduces tension in small alveoli more than in larger alveoli

9
Q

What is surfactant made of?

A

A phospholipid (Dipalmitoylphosphatidylcholine)

Surfactant proteins (SPA, SPB, SPC, SPD)