RRSPI RATION 



palate hangs down like a curtain, and when it is fully depressed 

 separates the mouth from the pharynx. 



The nose contains a cavity on each side separated by a 

 central partition. The cavity on each side is partly divided 

 into chambers by three 

 delicate scroll -like bones, 

 which project from the 

 sides. The cavities open 

 in front by the nostrils or 

 anterior nares to the 

 exterior, and behind by the 

 posterior nares into the 

 pharynx above the soft 

 palate. The soft palate 

 can be drawn up over the 

 posterior nares, so as to 

 shut off the cavity of the 

 nose from the pharynx. 

 In quiet respiration the air 

 is breathed through the 

 nostrils ; the ingoing air is 

 thus warmed by, and gains 

 moisture from, the walls of 

 the nasal chambers. 



The pharynx is a wide 

 funnel-shaped cavity, 4 

 inches long, the walls of 

 whirh consist of sheets of 

 striated muscle lined by 

 mucous membrane. At 

 its lower end it opens 

 behind into the oesophagus, 

 and in front into the 

 larynx, a chamber with 

 cartilaginous walls in which 

 the voice is produced, and 

 which opens below into the trachea. The opening into the 

 larynx is slit-like, and is the aperture of what is called the 

 glottis. Immediately above the glottis is a cartilaginous lid- 

 like structure, called the epiglottis, which is drawn down back- 



l 



FIG. 52. The upper air passages. Vertical 

 section. 



, vertebral column ; 6, oesophagus ; c, trachea ; 

 d, larynx ; e, epiglottis ; /, soft palate and 

 uvula ; g, opening of left Kustachian tube ; 

 //, opening of left lachrymal duct ; /, hyoid 

 bone ; k, tongue ; I, hard palate ; HI, n, base 

 of skull ; a, /, f, the three scroll-like or 

 turbin 



