84 ADVANCED PHYSIOLOGY 



through the nose or mouth, and thus easily become inflamed 

 by excessive cold, or by foreign particles in the air. 



There are other openings into the pharynx besides that from 

 the mouth; of these, two open from the nose just above the 

 soft palate, near the mid-line. At this upper end where 

 the nasalpassages enter, the pharynx cavity is not very largo 

 and is roofed over by the lower bone of the brain box, covered 

 by a soft membrane. Into this part of the pharynx project 

 innumerable hair-like structures, called cilia; Fig. 43. These 

 cilia are minute, transparent filaments which have the power 

 of lashing to and fro and creating a current in the mucus 

 on the surface of the cells. Particles of dust may thus be 

 moved along, and tears, which run down into the nose canals, 

 may also be hurried to the pharynx, where one becomes con- 

 scious of the liquid and spits it fiom the mouth or swallows it. 



These dust particles in the air are generally covered with 

 bacteria; and since the tonsils are deeply wrinkled, these bacteria 

 easily lodge in the crevices and provoke inflammation. It has 

 even been proven that 80% of diseased tonsils harbor the 

 type of bacteria which causes tuberculosis, and may thus 

 act as an entrance point for this most serious malady. 



In the upper part of the pharynx cavity on each side is a 

 minute opening through which a bristle can be thrust into a 

 canal leading to the ear. These small passages are called the 

 Eustachian tubes, and have much to do with hearing; Fig. 40. 



If one closes the nose passages by holding the nose between 

 the fingers, and then swallows, the noise in the ears shows that 

 a passage exists between them and the throat. When the 

 pharynx wall is sore and swollen (pharyngitis) , this canal may 

 become closed and a disagreeable noise be constantly heard. 



At the lower end of the pharynx are two comparatively 

 large openings. The front one is the glottis, which is the upper 

 end of the windpipe, and leads to the lungs; the one behind 

 that is in the gullet, or oesophagus opening, and leads to the 

 stomach. It is evident, then, that all food which leaves the 



