Expulsion of tracheal air
- Pronunciation
- /ik-SPUHL-shun of TRAY-kee-ul air/
- Category
- Physiology
Definition
The active discharge of air from the tracheal system during the expiratory phase of ventilatory movements in insects, driven by abdominal compression or dorsoventral thoracic flexion that increases internal pressure and forces gas outward through the .
Etymology
Latin expellere (to drive out) + Greek tracheia (rough, windpipe) + Old English air
Example
In large flying such as scarabs, expulsion of tracheal air through the mesothoracic during wing elevation helps unidirectionally flush carbon dioxide while minimizing convective cooling of the thoracic muscles.
Synonyms
- air expulsion
- tracheal discharge
Related Terms
- tracheal ventilation
- Spiracle
- abdominal pumping
- unidirectional airflow
- tracheal system
- respiratory cycle
- convective respiration
Usage Notes
Distinguished from passive diffusion by its dependence on muscular activity and pressure gradients; often paired with 'aspiration of tracheal air' to describe the complete ventilatory cycle. The term is typically used in comparative studies of insect respiratory mechanics and is especially relevant for large or active where diffusion alone is insufficient.