THE LARYNX . 233 



or fossa by a partition called the septum, the anterior portion of 

 the septum being formed by the triangular cartilage of the nose, 

 the remaining portion by bones the vomer and the vertical 

 plate of the ethmoid (Fig. 26). The openings upon the face are 

 the nares (anterior nares) and those at the back (looking into the 

 nasopharynx) are the choance (posterior nares). 



On the lateral wall of each nasal cavity are three turbinated 

 bones or shells (conchae), and three spaces or passages directly 

 underneath them, named as follows: the superior meatus (or 

 passage) beneath the superior concha (or shell) ; the middle meatus 

 beneath the middle concha; and the inferior meatus beneath the 

 inferior concha (Fig. 25). The upper part of each fossa is the 

 olfactory part; all below that is the respiratory part. 



Breath is the air from the lungs with all that it contains; breathing, then, 

 is producing air which has been passing through the lungs. 



The nasal cavities and all of the sinuses which communicate 

 with them are lined with mucous membrane, 

 which by the mucus on its surface, prevents 

 the drying effect of the air upon the pas- 

 sages, arrests foreign particles, and moder- 

 ates the temperature of the air on its way 

 to the lungs. As an organ of respiration, 

 the nose is important because nasal respira- 

 tion moistens, filters and warms the air we FIG. 156. CILIATED EPI- 

 breathe. THELIUM. (Stirling) . 



The mucous membrane of the nasal fossae is called the Schneiderian mem- 

 brane. It is ciliated in the respiratory part. In the olfactory part the 

 olfactory cells are found, which receive the impressions leading to the sense of 

 smell. For the nose as an organ of the sense of smell, and of voice, see 

 pp. 326 and 345. 



THE PHARYNX 



The pharynx is the space behind the nose, mouth, and larynx. 

 Its use is to transmit air from the nose, and food from the mouth. 

 As an air-passage it is included with the respiratory organs. (The 

 air passes from the nose through the pharynx to the larynx.) 



THE LARYNX 



The larynx is situated below the hyoid bone, in front of the 

 pharynx, and projects slightly forward in the neck. It is con- 



