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Insect Tracheal System
The insect tracheal system is a network of air-filled tubes that deliver oxygen directly to tissues. Unlike vertebrates, insects do not use blood to transport oxygen; instead, air enters through spiracles and travels through tracheae to reach cells, facilitating direct gas exchange without the need for alveoli.
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Spiracles
Spiracles are small openings on the surface of an insect's body that allow air to enter the tracheal system. They can open and close to regulate airflow and minimize water loss, which is crucial for maintaining hydration in terrestrial environments. Spiracles do not open into the body cavity but connect directly to tracheae.
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Tracheal Function During Movement
During activities like flight, insects can alter the volume of their tracheal system by dilating and constricting tracheae, which aids in ventilating the system. This 'breathing' mechanism helps increase oxygen delivery to tissues when metabolic demands are high, although it does not involve alveoli as in vertebrate lungs.
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