The trachea (IPA tr'eik-i-a), or windpipe, is a tube extending from the larynx to the bronchi in mammals, and from the pharynx to the syrinx in birds, carrying air to the lungs. It is lined with ciliated cells which push particles out and reinforced with cartilage rings.
In ill or injured persons, the natural airway formed by the trachea may be damaged or closed off. Intubation is the medical procedure of inserting an artificial tube into the trachea to permit breathing. See also choking.
In insects, each segment of the body has a pair of spiracles, each of which has a trachea behind it. Air moves into these small tubes through the spiracles. These tracheae branch and supply air to the tissues, where oxygen is absorbed into the body. Insects do not carry oxygen in their blood, as do vertebrates; this limits their size.
