210 



STUDIES IN PHYSIOLOGY 



the processes in the body just as surely as does an accumu- 



lation of ashes in a furnace. 

 Wastes given off by Lungs. 

 If one breathes on a cold 

 window pane, one finds that 

 the .glass becomes clouded 

 with vapor. This shows 

 that by expiration the body 

 gets rid of some of its waste 

 water. Carbon dioxid is like- 

 wise excreted from the lungs, 

 as one can easily demonstrate 

 by the milky appearance of 

 limewater into which the 

 breath has been blown. 



2. THE ORGANS OF RESPI- 

 RATION 



Course taken by the Air. 

 Air enters the body through 

 the two nostrils, and then 

 passes backward into the 

 throat cavity. In the lower 

 region of the throat is the 

 slitlike glot'tis opening, 

 through which, when the 

 epiglottis is raised, the air 



FIG. 97. Longitudinal Section of 

 Head and Neck, showing Food and 

 Air Passages. 



a = vertebral column. 



6 = esophagus. 



c = windpipe. 



d = larynx. 



e = epiglottis. 



/= soft palate and uvula. 



g = opening of left Eustachian enters the lar'ynx, or voice 



box. The latter, commonly 

 known as " Adam's apple," 

 projects somewhat on the 

 ventral side of the neck, and 

 below the larynx one can 

 feel the rings of cartilage 

 Just above the level of the heart the 



tube. 



h opening of left tear duct. 

 i = hyoid bone. 

 k = tongue. 

 I = hard palate. 

 m, n = base of skull. 

 >,p,g = upper, middle, and lower 

 turbinate bones. 



about the windpipe. 



