Inmammals, the trachea begins at the lower part of thelarynx and continues to the lungs. There it branches into the right and leftbronchi.Inflammation of the trachea can lead to other conditions, such astracheitis, which is the inflammation of the linings of the trachea.
Tracheal system of dissectedcockroach. The largest tracheae run across the width of the body of the cockroach and are horizontal in this image.Scale bar, 2 mmThe tracheal system branches into progressively smaller tubes, here supplying thecrop of the cockroach. Scale bar, 2 mm
Theinvertebrate trachea refers to the openrespiratory system ofterrestrialarthropods. It consists ofspiracles, tracheae, andtracheoles that takemetabolic gases to and from tissues.[1] The distribution of spiracles varies, but in general each segment of the body has only one pair of spiracles, each of which connects to anatrium and has a relatively large tracheal tube behind it.
The smallest tubes, tracheoles, penetrate cells anddiffuse water,oxygen, andcarbon dioxide.Gas may be moved actively or by passive diffusion. Unlikevertebrates,insects do not generally carry oxygen in theirhaemolymph.[2]This is one of the factors that may limit their size.
A tracheal tube may contain ridge-like circumferential rings oftaenidia in variousgeometries such as loops orhelices. In thehead,thorax, orabdomen, tracheae may also be connected to air sacs. Many insects, such asgrasshoppers andbees, which actively pump the air sacs in their abdomen, are able to control the flow of air through their body. In some aquatic insects, the tracheae exchange gas through the body wall directly, in the form of agill, or function as normal, via aplastron. Despite being internal, the tracheae of arthropods are shed during moulting (ecdysis).
↑Wasserthal, Lutz T. 1998. Chapter 25: The open hemolymph system of Holometabola and its relation to the tracheal space. InMicroscopic anatomy of invertebrates. Wiley-Liss.ISBN0-471-15955-7
