340 



COMPARATIVE ANATOMY 



The respiratory blood vessels of the lung are branches of the pulmonary 

 arteries and veins. The bronchial artery and vein supply the connective 

 tissues of the lungs. The innervation of the lung is through branches 

 of the vagus and of the sympathetic. 



On the outside of the lung the pleura, corresponding to the peritoneal 

 lining of the abdominal cavity, consists of a subserous connective tissue 



Epithelium. 



Tunica Circular 



propria. muscle fibers, i. 





■:^<w:-i-f*s!».-..,. 4 X, ^^ 



s-^^M...ill^%^ 



— AlveolL 





Fat cells. 



Cartilage. 



Connective tissue. 

 Bronchial gland. 



Duct of gland. 



Fig. 284. — Cross section of a bronchus 2 mm. in diameter, from a child. (From 

 Bremer's "Text-book of Histology.") 



which extends into the lobules of the lung, and of an external epithelial 

 serosa. The pulmonary pleura is reflected back on the inside of the 

 chest as the parietal pleura. 



Larynx. The larynx or voice-box hes between the root of the tongue 

 and the trachea, and opens into the pharynx by the glottis. Nine carti- 

 lages support it, the unpaired epiglottic, thyroid, and cricoid cartilages, 

 and the paired arytenoids, corniculate, and cuneiform cartilages. Small 

 paired triticeous cartilages also sometimes are found. Numerous muscles 

 are attached, some extrinsic and some intrinsic. The extrinsic muscles 

 are chiefly to lift the larynx in swallowing. Among the intrinsic 



