Advertisement

Journal of Comparative Physiology B

, Volume 157, Issue 3, pp 307–314 | Cite as

Gas exchange and air flow in the lung of the snake,Pituophis melanoleucus

  • Jerry N. Stinner
Article

Summary

Gas samples from various regions of the lung were obtained throughout the breathing cycle inPituophis melanoleucus. Changes in CO2 concentration during the interbreath period differed markedly along the length of the lung. In general, the largest and most rapid increases in CO2 tension were measured at the cranial end of the vascular lung. Further caudad in the vascular lung, the increase was slower and did not reach mixed venous CO2 tension before exhalation. In animals exhibiting the lowest breathing frequencies and presumably larger tidal volumes, the region of gas exchange extended into the cranial portion of the air sac. There was little or no change in gas tensions within the remaining caudal regions of the air sac. Measurement of exhaled CO2 and O2 tensions at the nares confirmed the longitudinal gradient in gas exchange and also demonstrated the sequential emptying of the lung. Large regional differences in the ratio of blood flow to alveolar volume are probably responsible for the gradients in lung gases.

Interpretation of N2 clearance curves in terms of two freely communicating compartments demonstrated the presence of a ventilation inequality. Consistent with this was the lack of body wall contractions between breaths while animals were resting. However, just prior to and during activity body wall contractions not associated with breathing often occurred and resulted in pressure excursions in the lung of ca. five mm H2O. In addition, the heart beat results in a pressure change within the lung of ca. 0.2 mmH2O which may be significant in gas mixing.

Keywords

Breathing Frequency Breathing Cycle Alveolar Volume Clearance Curve Large Tidal Volume 
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.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Brattstrom BH (1965) Body temperatures of reptiles. Am Midl Nat 73:376–422Google Scholar
  2. Burggren WW, Glass ML, Johansen K (1978) Intrapulmonary variation of gas partial pressures and ventilation inequalities in chelonian reptiles. J Comp Physiol 126:203–209Google Scholar
  3. Crawford EC Jr, Gatz RN, Magnussen H, Perry SF, Piiper J (1976) Lung volume, pulmonary blood flow and carbon monoxide diffusing capacity of turtles. J Comp Physiol 107:169–178Google Scholar
  4. Donnelly P, Woolcock AJ (1977) Ventilation and gas exchange in the carpet python,Morelia spilotes variegata. J Comp Physiol 122:403–418Google Scholar
  5. Donnelly P, Woolcock AJ (1978) Stratification of inspired air in the elongated lungs of the carpet python,Morelia spilotes variegata. Respir Physiol 35:301–315Google Scholar
  6. Duncker HR (1977) General morphological principles of amniotic lungs. In: Piiper J (ed) Respiratory Function in Birds, Adult and Embryonic. Springer, Berlin Heidelberg New York, pp 2–15Google Scholar
  7. Fowler WS, Cornish ER Jr, Kety SS (1952) Lung function studies. VIII. Analysis of alveolar ventilation by pulmonary N2 clearance curves. J Clin Invest 31:40–50Google Scholar
  8. Fukuchi Y, Roussos CS, Macklem PT, Engel LA (1976) Convection, diffusion and cardiogenic mixing of inspired gas in the lung; an experimental approach. Respir Physiol 26:77–90Google Scholar
  9. Gratz RK, Ar A, Geiser J (1981) Gas tension profile of the lung of the viper,Vipera xanthina Palestinae. Respir Physiol 44:165–176Google Scholar
  10. Hicks JW, Glass ML, Riedesel ML (1979) Assessment of alveolar ventilation in garter snakes,Thamnophis elegans. Fed Proc 38:1246Google Scholar
  11. Kardong KV (1972) Morphology of the respiratory system and its musculature in different snake genera (Part II)Charina bottae. Gegenbaurs Morphol Jahrb Leipzig 117:364–376Google Scholar
  12. Rahn H, Garey WF (1973) Arterial CO2, O2, pH and HCO3 values of ectotherms living in the Amazon. Am J Physiol 225:735–738Google Scholar
  13. Rossier PH, Buhlmann A (1955) The respiratory dead space. Physiol Rev 35:860–876Google Scholar
  14. Seymour RS (1978) Gas tensions and blood distribution in sea snakes at surface pressure and at simulated depth. Physiol Zool 51:388–407Google Scholar
  15. Sikand RS, Magnussen H, Scheid P, Piiper J (1976) Convective and diffusive gas mixing in human lungs: experiments and model analysis. J Appl Physiol 40:362–371Google Scholar
  16. Spragg RG, Ackerman R, White FN (1980) Distribution of ventilation in the turtlePseudemys scripta. Respir Physiol 42:73–86Google Scholar
  17. Stinner JN (1982a) Ventilation, gas exchange and blood gases in the snake,Pituophis melanoleucus. Resp Physiol 47:279–298Google Scholar
  18. Stinner JN (1982b) Functional anatomy of the lung of the snake,Pituophis melanoleucus. Am J Physiol 243:R251-R257Google Scholar
  19. West JB (1969) Ventilation-perfusion inequality and overall gas exchange in computer models of the lung. Respir Physiol 7:88–110Google Scholar
  20. West JB (1985) Respiratory physiology-the essentials (3rd edition). Williams and Wilkins, pp 183Google Scholar
  21. West JB, Flowler KT, Hugh-Hones P, O'Donnell TV (1957) The measurement of the inequality of ventilation and perfusion in the lung by the analysis of single expirates. Clin Sci 16:549–565Google Scholar

Copyright information

© Springer-Verlag 1987

Authors and Affiliations

  • Jerry N. Stinner
    • 1
  1. 1.Division of BiologyUniversity of CaliforniaRiversideUSA

Personalised recommendations