Mechanisms of Intracardiac Shunting in Reptiles: Pressure vs Washout Shunting

  • J. W. Hicks
  • G. M. Malvin
Part of the Advances in Comparative and Environmental Physiology book series (COMPARATIVE, volume 21)


In adult mammals and birds, the right and left sides of the heart are normally separate. Intracardiac shunting, which is usually detrimental, results only from congenital abnormalities of the heart and great vessels. In contrast, intracardiac shunting normally occurs in noncrocodilian reptiles. The complex and unique anatomy of these animals can allow both the systemic venous blood to bypass the lungs as well as the pulmonary venous blood to bypass the systemic circulation. It is not uncommon for these bypasses to comprise most of the cardiac output. The success of this vertebrate class indicates that intracardiac shunting is not detrimental to these animals, and may, in fact, provide certain survival advantages (Burggren 1985).


Aortic Arch Pulmonary Vascular Resistance Vagal Stimulation Pulmonary Blood Flow Systemic Arch 
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Copyright information

© Springer-Verlag Berlin Heidelberg 1995

Authors and Affiliations

  • J. W. Hicks
    • 1
  • G. M. Malvin
    • 2
  1. 1.Department of Ecology and Evolutionary BiologyUniversity of CaliforniaIrvineUSA
  2. 2.Oxygen Transport ProgramLovelace Medical FoundationAlbuquerqueUSA

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