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An aerodynamic valve in the avian primary bronchus
N Wang1, R B Banzett, C S Nations
1Respiratory Biology Program, Harvard School of Public Health, Boston, Massachusetts 02115.
The Journal of Experimental Zoology
|July 11, 1992
Summary
The segmentum accelerans in geese acts as an inspiratory valve, controlling airflow. Elevated carbon dioxide levels cause this airway constriction to dilate, suggesting physiological regulation of breathing.
Area of Science:
- Avian respiratory physiology
- Comparative anatomy
Background:
- The primary bronchus in birds contains a unique structure called the segmentum accelerans.
- This segment is located at the caudal end of the primary bronchus.
Purpose of the Study:
- To investigate the function of the segmentum accelerans in geese.
- To explore the physiological control mechanisms of the segmentum accelerans.
Main Methods:
- Experimental manipulation of carbon dioxide levels.
- Observation of changes in the luminal diameter of the segmentum accelerans.
Main Results:
- The segmentum accelerans functions as an inspiratory aerodynamic valve, accelerating airflow.
- Elevated CO2 levels lead to dilation of the segmentum accelerans.
- Dilation is likely mediated by smooth muscle relaxation.
Conclusions:
- The segmentum accelerans plays a critical role in regulating airflow during inspiration in geese.
- Physiological control, particularly via CO2, allows for adaptive modulation of this aerodynamic valve across varying ventilatory demands.
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