RESPIRATION PHYSIOLOGY: ALVEOLAR GAS EXCHANGE
Quantitative Relations

QUANTITATIVE RELATIONS

A. Alveolar Air Equation (relation between PI-O2, PA-O2, PA-CO2) -- simplified

PA-O2 = PI-O2 - PA-CO2 / R breathing air

PA-O2 = PI-O2 - PA-CO2 breathing pure oxygen

Note the relation between alveolar O2 and alveolar CO2

Summary:

RsAlvl07.gif (12896 bytes)

Examples =>

B.    Fick's Law (relation between production/consumption & alveolar gas)

V'O2 = V'E ( FI-O2 - FE-O2 ) = V'A ( FI-O2 - FA-O2 )

V'CO2 = V'E ( FE-CO2 - FI-CO2 ) = V'A ( FA-CO2 - FI-CO2 )

Note: FI-CO2 is zero (unless breathing gas enriched with carbon dioxide), so

FA-CO2 = V'CO2 / V'A

Note the relation between V'A and FA-CO2 & FA-O2

RsAlvlQntv.htm -- A4B03

© AC Brown 2004