THE AVIAN RESPIRATORY SYSTEM - A UNIQUE MODEL FOR STUDIES OF RESPIRATORY TOXICOSIS AND FOR MONITORING AIR-QUALITY

There are many distinct differences (morphologic, physiologic, and mec hanical) between the bird's lung-air-sac respiratory system and the ma mmalian bronchoalveolar lung. In this paper, we review the physiology of the avian respiratory system with attention to those mechanisms tha t may lead to significantly different results, relative to those in ma mmals, following exposure to toxic gases and airborne particulates. We suggest that these differences can be productively exploited to furth er our understanding of the basic mechanisms of inhalant toxicology (g ases and particulates). The large mass-specific gas uptake by the avia n respiratory system, at rest and especially during exercise, could be exploited as a sensitive monitor of air quality. Birds have much to o ffer in our understanding of respiratory toxicology, but that expectat ion can only be realized by investigating, in a wide variety of avian taxa, the pathophysiologic interactions of a broad range of inhaled to xicants on the bird's unique respiratory system.