Tracheal breathing is the type of breathing in which gas exchange occurs through the trachea.
This type of breathing occurs in insects, some ticks, spiders and centipedes.
The tracheas are thin, spiral and hollow tubes with chitinous reinforcements. They open directly on the body’s surface, along the chest and abdomen, in pores called spiracles .
The tracheas form a highly branched system, allowing oxygenation to all parts of the animal’s body.
This type of breathing has nothing to do with the circulatory system. The tracheas guarantee gas exchange directly with the cell.
How does tracheal breathing occur?
Atmospheric air enters the animal’s body through the spiracles and reaches the trachea . The air is conducted along the trachea to its branches, the trachea, where they reach the cells.
In this way, oxygen gas is transported to the cell and carbon dioxide is removed through simple diffusion.
Insects can control their breathing by opening and closing the spiracles, with muscle contractions. This condition is important for survival in dry environments, as it prevents water loss.
Philotracheal breathing
Many spiders have phyllotrachea or foliaceous lungs, formed by sheets of tissue where the hemolymph circulates. In this case, we have philotracheal breathing.
The philotraches are located inside the abdomen and communicate with the outside through a respiratory pore.
Atmospheric air enters the respiratory pore and circulates between the philotracheal blades, oxygenating the hemolymph and removing carbon dioxide.