PHYSIOLOGY. 



Position of Organs during Respiration. In quiet 

 respiration the tongue nearly fills the mouth. The base 

 of the tongue is nearly covered by the soft palate, which 

 curves downward from the hard palate, and by the epi- 

 glottis projecting upward from below. The glottis is 

 open and the gullet is closed. Air enters the nostrils, 

 passes along the nasal passages above the hard palate, 

 back of the soft palate and epiglottis, through the open 

 glottis into the windpipe, and on to the lungs. 



Hard Palate - 



Eustachian Tube 

 Soft Palate, Down 



Pharynx 

 "L Epiglottis, Raised 



I,..; Gullet, Closed 



Glottis, Open 



Fig. 58. Diagram, showing the Positions of the Organs of the Mouth and 

 Throat during Breathing. 



The Process of Swallowing. When the morsel of 

 food is ready to be swallowed the tongue pushes it back 

 into the pharynx ; the soft palate is raised to shut off the 

 passage into the nasal cavity ; the larynx is pulled upward 

 and forward ; the epiglottis is pulled down over the glottis, 

 or opening of the windpipe ; and the base of the tongue 

 extends back over the epiglottis; thus the air passages, 

 above and below, are shut off, and the food passes over 

 the epiglottis into the gullet. The muscles of the pharynx 



