Question

50) Assume that the atmospheric pressure outside the body is 760 mm Hg. Assuming you are inhaling, the percent of gases in the air is as follows: N2-78% O2-20% CO,-0.04%. If the airways vapor pressure is about 5% of atmospheric pressure, compare oxygen and carbon dioxide diffusion rate at the alveolar-capillaries interface given the Vco2 following parameters PCO2Cap 45mmHg PCO2Al 40mmHg PO2cap = 45mmHg ko, 0.045 x kco Co2 02 02 02 co2 Fick's law of diffusion: V = k × A ×

Answer 1

Fick's law

Vo2= K*A*P2(02)-P1(o2)/D

= 0.045*k CO2 * A*P2(O2)-P1(O2)/D

Vco2"=k*A*P2(CO2)-P1(CO2)/D

V O2/ V CO2 =0.045* P2(02)-P1(o2)/ P2(CO2)-P1(CO2)

(Everything else gets cancelled)

Pcap(O2)= 45

Palv(O2)= 20% of atmospheric pressure =20*760/100=154

Pcap(CO2)=45

Palv(CO2)=40

V O2/ VCO2= 154-45*0.045/ 45-40

= 109*0.045/5

=9.81