Anatomy and Cell Biology 3309 Chapter Notes - Chapter 18: Afferent Nerve Fiber, Bombesin, Foregut
23 Jan 2017
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The trachea is a short, flexible, air tube about 2. 5 cm in diameter and about 10 cm long. It serves as a conduit for air; additionally, its wall assists in conditioning inspired air. The trachea extends from the larynx to about the middle of the thorax, where it divides into the two main (primary) bronchi. The lumen ofthe trachea stays open because ofthe arrangement of the series of cartilaginous rings. A unique feature of the trachea is the presence of a series of c-shaped hyaline cartilages that are stacked one on top of each other to form a supporting structure. These cartilages, which might be described as a skeletal framework, prevent collapse ofthe tracheal lumen, particularly during expiration. Fibroelastic tissue and smooth muscle, the trachealis muscle, bridge the gap between the free ends of the c-shaped cartilages at the posterior border of the trachea, adjacent to the esophagus.
