THE TRACHEA AND LUNGS 



141 



The bronchi resemble the trachea in general structure, being 

 composed of similar rings of cartilage and fibrous tissue. The 

 cartilages, too, are incomplete behind. 



Fig. 130. The Trachea. Front. 



h, hyoid bone ; if, thyroid cartilage 1 ; c, cri- 

 coid ; e, epiglottis ; tr, trachea ; b and 

 b', bronchi. 



Fig. 131. The Trachea. Back. 



a, arytenoid cartilages ; h, hyoid bone ; 

 if, thyroid cartilage ; c, cricoid ; e, epi- 

 glottis ; tr, trachea ; b and /', bronchi. 



The bronchi subdivide into smaller and smaller tubes, called 

 the bronchial tubes, which penetrate every part of the lungs, and 

 finally terminate in groups of air-cells. In the bronchial tubes 



