Chap. xxviii.] ORGANS OF RESPIRATION. 215 



of lymphatics, called the superficial lymphatics. 

 Numerous branches pass between this network and 

 those of the interlobular lymphatics. 



CHAPTER XXVIII. 



THE ORGANS OF RESPIRATION. 



283. I. The larynx. The supporting frame- 

 work of the larynx is formed by cartilage. In the 

 epiglottis the cartilage is elastic and reticulated, 

 i.e., the cartilage plate is perforated by numerous 

 smaller and larger holes. The cartilages of Santorini 

 and Wrisbergii, the former attached to the top of 

 the arytenoid cartilage, the latter enclosed in the 

 aryteno-epiglottidean fold, are also elastic. The 

 thyroid, cricoid, and arytenoid cartilages are hyaline. 

 All these are covered with the usual perichondrium. 



A small nodule of elastic cartilage is ^enclosed in 

 the front part of the true vocal cord. This is the 

 cartilage of Luschka. 



The mucous membrane lining the cavity of the 

 larynx (Fig. 126) has the following structure : 



The epithelium covering the free surface is 

 stratified columnar ciliated, i.e., the most superficial 

 layer is made up of conical cells with cilia on their 

 surface ; then between the extremities of these cells 

 are wedged in spindle-shaped and inverted conical cells. 

 Numerous goblet cells are found amongst the superficial 

 cells. The two surfaces of the epiglottis and the 

 true vocal cord are covered with stratified pavement 

 epithelium. 



Underneath the epithelium is a basement men- 

 brane separating the former from the mucous mem- 

 brane proper. 



