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The air tube extending from the larynx into the thorax (level of the fifth or sixth thoracic vertebra) where it bifurcates into the right and left main bronchi. The t. is composed of 16–20 rings of hyaline cartilage connected by a membrane (annular ligament); posteriorly, the rings are deficient for one-fifth to one-third of their circumference, the interval forming the membranous wall being closed by a fibrous membrane containing smooth muscular fibers. Internally, the mucosa is composed of a pseudostratified ciliated columnar epithelium with mucous goblet cells; numerous small mixed mucous and serous glands occur, the ducts of which open to the surface of the epithelium. SYN: windpipe. [G. tracheia arteria, rough artery]
- saber-sheath t. a type of tracheal collapse seen in chronic obstructive pulmonary disease in which there is an increase in the outer posterior tracheal dimension with side-to-side narrowing involving the lower two-thirds of the t..
- scabbard t. a deformity of the t. caused by flattening and approximation of the lateral walls, producing more or less pronounced stenosis.
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tra·chea 'trā-kē-ə, Brit also trə-'kē-ə n, pl tra·che·ae -kē-.ē also tra·che·as the main trunk of the system of tubes by which air passes to and from the lungs that is about four inches (10 centimeters) long and somewhat less than an inch (2.5 centimeters) in diameter, extends down the front of the neck from the larynx, divides in two to form the bronchi, has walls of fibrous and muscular tissue stiffened by incomplete cartilaginous rings which keep it from collapsing, and is lined with mucous membrane whose epithelium is composed of columnar ciliated mucus-secreting cells called also windpipe
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n.
the windpipe: the part of the air passage between the larynx and the main bronchus, i.e. from just below the Adam's apple, passing behind the notch of the sternum (breastbone) to behind the angle of the sternum. The upper part of the trachea lies just below the skin, except where the thyroid gland is wrapped around it.
• tracheal adj.
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tra·chea (traґke-ə) pl. traґcheae [L., from Gr. tracheia artēria] 1. [TA] the cartilaginous and membranous tube descending from the larynx and branching into the right and left main bronchi. It is kept patent by a series of about twenty transverse horseshoe-shaped cartilages. Called also windpipe. 2. one of a system of minute tubes ramifying throughout the body of a terrestrial arthropod and delivering air to the tissues; called also tracheal tubule. See also tracheole.
Trachea, transverse section.
Medical dictionary. 2011.