Trachea

Definition

In arthropods, a cuticle-lined, air-conducting tube that forms the primary channel of the tracheal respiratory system. Tracheae arise from spiracles and branch internally into progressively finer tracheoles that deliver oxygen directly to tissues. In insects, tracheae are typically reinforced with spiral or annular taenidia that prevent collapse while permitting flexibility. The system allows most terrestrial arthropods to respire without relying on blood-borne oxygen transport.

Etymology

From New Latin, from Greek tracheia (arteria), 'rough (artery)', referring to the cartilaginous rings of the vertebrate windpipe; applied by analogy to the ring-strengthened tubes of insects.

Example

In a grasshopper, paired lateral tracheae run the length of the body, giving off segmental branches that supply flight muscles with oxygen during sustained jumping or flying.

Related Terms

• Spiracle
• Tracheole
• Taenidium
• book lung
• Plastron
• Cuticle
• Respiratory system

Usage Notes

Distinguished from the vertebrate trachea (windpipe) by its cuticular rather than cartilaginous construction and by its role in a fundamentally different respiratory mechanism. Arthropod tracheae are not ciliated and do not connect to lungs; they terminate in fluid-filled tracheoles where gas exchange occurs. The term is sometimes applied loosely to similar air channels in some arachnids and myriapods, though these groups may show substantial structural variation.