Consequences of the O2-CO2 Dissociation Curves for Gas Exchange in Avian and Mammalian Lung at Various Altitudes

  • Aart Zwart
  • Ed Hoorn
Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 191)


Gas exchange in avian and mammalian lung was studied with computer simulations using mutually dependent O2-CO2 dissociation curves. The mammalian lung was simulated with an ideal mixing unit. The model of the avian lung consisted of 25 ideal mixing units placed in series with respect to the ventilation but placed in parallel with respect to the perfusion (cross-current arrangement). The consequence of the right shift in the avian oxygen dissociation curve, if compared with the human dissociation curve, was studied by application of both dissociation curves to the avian lung model. The influence of a decreased tension of oxygen in the inspired air was studied under conditions of constant Pv̄CO2 (48 mmHg), Pv̄O2 (30 mmHg), RQ (0.70) and approximately constant levels of PaCO2.

At sea-level the avian lung needs 80 per cent of the alveolar ventilation and 64 per cent of the cardiac output to transport the same amount of gas if compared with the mammalian lung. The difference in the need for cardiac output resulted from the right shift in the dissociation curve of avian blood.

Changing PIO2 from 115 mmHg (2000 m) to 100 mmHg (3000 m) showed a dramatic difference in the performance of the two lung models. The mammalian lung model needed a more than eight fold increase in cardiac output whereas the avian lung model needed less than a three fold increase to maintain a RQ of 0.7. This difference could be ascribed to the Haldane effect in combination with the cross-current arrangement. The Haldane effect was also responsible for an end expired CO2 tension which exceeded the mixed venous CO2 tension.


Dissociation Curve Lung Model Mixed Venous Blood Muscovy Duck Lung Simulation 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Davies, G.D., and Dutton, R.E., 1975, Gas-blood PCO2 gradients during avian gas exchange, J Appl Physiol 39: 405–410.PubMedGoogle Scholar
  2. Gurtner, G.H., Song, S.H., and Farhi, L.E., 1969, Alveolar to mixed venous PCO2 differences under conditions of no gas exchange, Respir Physiol 7: 173–187.PubMedCrossRefGoogle Scholar
  3. Hazelhoff, E.H., 1943, Structure and function of the lung of birds, Versl. Gewone Vergad. Afd. Natuurk, Kon Ned Akad Wet 52: 391–400 (Poultry Sci 1951, 30: 3–10, English translation).Google Scholar
  4. Kelman, G.R., 1966, Digital computer subroutine for the conversion of oxygen tension into saturation, J Appl Physiol 21: 1375–1376.PubMedGoogle Scholar
  5. Kelman, G.R., 1967, Digital computer procedure for the conversion of PCO2 into blood CO2 content, Respir Physiol 3: 111–115.PubMedCrossRefGoogle Scholar
  6. Kinne, F.L., and Seagrave, R.C., 1974, Effects of mixing patterns in respiratory gas exchange, J Appl Physiol 36: 698–705.PubMedGoogle Scholar
  7. Piiper, J., and Scheid, P., 1975, Gastransport efficacy of gills, lung and skin: Theory and experimental data, Respir Physiol 23: 209–221.PubMedCrossRefGoogle Scholar
  8. Scheid, P., and Piiper, J., 1970, Analysis of gas exchange in the avian lung: theory and experiments in the domestic fowl, Respir Physiol 9: 246–262.PubMedCrossRefGoogle Scholar
  9. Scheipers, G., Kawashiro, T., and Scheid, P., 1975, Oxygen and carbon dioxide dissociation of duck blood, Respir Physiol 24: 1–13.PubMedCrossRefGoogle Scholar
  10. Zwart, A., and Luijendijk, S.C.M., 1982, Excretion-retention diagram to evaluate gas exchange properties of vertebrate respiratory systems, Am J Physiol (Regulatory Integrative Comp Physiol 12): R329–R338.Google Scholar

Copyright information

© Plenum Press, New York 1985

Authors and Affiliations

  • Aart Zwart
    • 1
  • Ed Hoorn
    • 1
  1. 1.Dept. of Plumonary Diseases, Pathophysiological LaboratoryErasmus UniversityRotterdamThe Netherlands

Personalised recommendations