Bronchial bifurcations and respiratory mass transport.

A new transport mechanism explains the importance of the shape of bronchial bifurcations in the transfer of gases and particles between the atmosphere and the alveoli. Photographs of flow visualization experiments illustrate the effect in models of bronchial branching. The mechanism provides a means of nondiffusional transport that helps to explain normal respiratory exchange of gases as well as successful ventilation with very low tidal volumes, as in some lung diseases and in the high-frequency panting of dogs.