exam 2 Ch 17 Flashcards
two major functions of pulmonary diffusion
replenishes blood oxygen supply
removes carbon dioxide from blood
at rest how much blood do lungs receive
4-6 L blood/min
lung mean arterial pressure at rest
15 mmHg
Why do the lungs have a small pressure gradient
they have thinner vessel walls
Standard atmospheric pressure
760 mmHg
Daltons law
total air pressure = PN2 + PO2 + PCO 2
AIr percentages
N2 = 79.04%
O2 = 20.93
CO2 = 0.03%
Total in standard atmosphereic P
N2
O2
CO2
N2 - 600.7 mmHg
O2 - 159.1 mmHg
CO2 - 0.2 mmHG
Gases dissolve in liquids in proportion to partial P
Depends on temp
Solubility in blood is constant at given temp
Henrys Law
Most importatn factor for determing gas exchange
drives gas diffusion
partial pressure gradient
PO2 gradient across respiratory membrane
65 mmHg
Rate of diffusion is proportional to surface area and partial pressure gas gradient
Flicks law
PCO2 gradient
6 mmHg
Does CO2 diffuse easier despite lower gradient
yes
O2 diffusion capacity
O2 volume diffused per min per mmHg of gradient
Resting O2 diffusion capacity
231 mL O2 / min for 11 mmHg gradient
As venous O2 decreases what happens
PO2 bigger gradient
Diffusion capacity increases by 3 times resting rate
At rest how much of the lung is getting blood flow for lung perfusion
only bottom 1/3 of lung (because of gravity)
What happens to lung perfusion during exercise
systemic blood pressure increases which opens up 2/3 perfusion
Pulmonary artery PCO2
Alveolar PCO2
46 mmHG
40mmHG
How much greater is the CO2 diffusion constant compared to O2
20 times
