SYSTEMATIC SYNTHESIS OF TISSUES INTO ORGANS. 333 



cles extend in various directions, forming the chief part 

 of the immediate walls of the pharynx, as illustrated by 

 Figs. 5, 7, PL 19. 



968. THE PHARYNX is LINED with mucous membrane, 

 continuous with that of the nostrils, of the middle ear, 

 of the mouth, of the windpipe, and of the resophagus ; 

 it partakes of the nature of all those linings, and is very 

 apt to partake, more or less, of their condition in dis- 

 ease, while its diseases are liable to extend to them. 



969. Inf. The physician will frequently look into the throat to 

 enable him to judge of the state of the parts with which its lining is 

 continuous. 



970. THE LARYNX is a small part of the windpipe, 

 that has no other relation to breathing than has been 

 indicated by the opening and closure of its upper orifice, 

 and, as an organ of speech, can best be described after 

 the breathing apparatus has been constructed. 



971. THE TRACHEA is a tube commencing from the 

 lower portion of the larynx, that is a complete ring, and 

 extends down into the chest, where it divides into two 

 branches, or Bronchii. 



972. THE TRACHEA is constructed of a framework 

 of C-shaped cartilages, connected to each other by white 

 sinewy fibres, closed at the back part by elastic and some 

 muscular fibres, and finished by a lining of mucous mem- 

 brane, in which there are a great number of minute 

 mucous glands. 



973. THE LUNGS are organs for bringing the air 

 and blood within the compass of the action of each 

 other; they are therefore situated on each side of the 

 heart, and at the lower extremity of the air-passages. 



974. THE LUNGS ARE CONSTRUCTED (see Fig. 218) of 

 divisions of the bronchii, 4, 5 ; of air-cells ; of capilla- 

 ries ; of arteries, 13, 14; of veins, 17, 18, 19, 20; of 

 sinewy tissue, white and elastic (Fig. 43), binding all 



968. How is ? 969. Why look into throat ? 970. What is ? 971. What is ? 

 9T2. How is constructed ? 973. What are ? 974. How are ? 



