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Inspiratory valving in avian bronchi: aerodynamic considerations
J P Butler1, R B Banzett, J J Fredberg
1Department of Environmental Science and Physiology, Harvard School of Public Health, Boston, MA 02115.
Respiration Physiology
|May 1, 1988
Summary
Avian lungs achieve unidirectional airflow using aerodynamic valves. Gas convective inertial forces are sufficient to create the inspiratory valve, with heuristic arguments for expiratory valve mechanisms.
Area of Science:
- Comparative physiology
- Avian respiration
- Fluid dynamics
Background:
- The avian respiratory system is unique, featuring unidirectional airflow.
- This flow is hypothesized to be regulated by aerodynamic valves within the lung.
- Previous research has explored this concept, but detailed mechanisms remain unclear.
Purpose of the Study:
- To review the history and evidence for aerodynamic valves in avian lungs.
- To present a fluid dynamic analysis of mechanisms potentially responsible for unidirectional airflow.
- To investigate the role of gas convective inertial forces in inspiratory valving.
Main Methods:
- Literature review of the aerodynamic valve hypothesis in avian respiration.
- Semi-quantitative fluid dynamic modeling of airflow within the avian lung.
- Analysis of gas convective inertial forces and their potential role in valving.
Main Results:
- Calculations demonstrate that gas convective inertial forces can effectively create an inspiratory valve.
- The study details the potential mechanisms and dependencies of the inspiratory valve.
- Heuristic arguments are presented for the mechanisms underlying expiratory valving.
Conclusions:
- Aerodynamic valves, driven by gas convective inertial forces, are a plausible mechanism for unidirectional airflow in avian lungs.
- The findings provide a detailed understanding of inspiratory valve function.
- Further investigation into expiratory valve mechanisms is warranted.