SECT. 174.] VESSELS AND NERVES. TRACHEA. 



379 



transversus, and a considerable number of them present themselves 

 externally upon the ventricles of Morgagni, behind and above the 

 ligaments of the ventricles. The secretion of these glands is pure 

 mucus, without any morphological elements, as Ave have before seen 

 in the glands of the buccal cavity. 



The larynx is plentifully supplied Fig . 157. 



with vessels and nerves. The former 

 present, in the mucous membrane, the 

 same condition as in the pharynx, and. 

 ultimately form a superficial net-work 

 with capillaries of o - oo3"' to o - oc>4'" 

 in diameter. The lymphatics are nu- 

 merous and proceed to the deeper 

 cervical glands. With regard to the 

 n rves, we learn from Bidder-Volk- 

 mann, that the special nerve of sen- 

 sation, the laryngeus superior, contains 

 fine nerve-fibres, and the special mo- 

 tor nerve, laryngeus inferior, much 

 thicker ones. Their terminations are 

 nut with in the muscles, the peri- 

 chondrium, and especially in the mu- 

 cous membrane; they present the 

 same arrangement in the last as in the 

 pharynx (see p. 314), and upon the 

 branches to the epiglottis, microscopic 

 ganglia may be detected. 



The glands of the larynx, and of the air- 

 sages in general, are frequently altered in 

 catarrhs, so that their vesicles measure up to 

 o - c8'" or even o"i5'" in diameter, and are fil- 

 led with small roundish cells, which are, 

 perhaps, to be compared with the 'mucous 

 corpuscles ' formed upon the surfaces of mu- 

 cous membranes. 









5 



Perpendicular section through 

 the anterior wall of the human 

 trachea; magnified 45 times, a. 

 Fibrous envelope, bed. Cartilage. 

 6. External layer with fiat cells. 

 d. Internal layer with elongated 

 elements, e. Submucous tissue. 

 /. Part of a mucous gland, g. 

 Elastic longitudinal fibrous layer. 

 h. Epithelium, on which the cilia 

 are not visible, i. Opening of a 

 gland. 



174. The trachea and its two 

 branches are connected with the neigh- 

 bouring parts by a connective tissue, rich 

 in beautiful elastic fibres, and are directly surrounded by a dense, 

 elastic fibrous tissue. This layer covers the semi-circular cartilages 

 as a perichondrium, connects the rings with each other, and, as a 



