CHAPTER XII 

 THE RESPIRATORY SYSTEM 



The respiratory system may be said to comprise a true respiratory 

 organ, the pulmonary alveoli, in which the interchange of gases between 

 the air and the blood occurs, and a system of duct-like passages leading 



Superior lurbinate bone 



Olfactory nerte 



Nasal sin 



Sphenoidal sinus 

 Nasal nerve 



FIG. 280. PHOTOGRAPH OF Azoux MODEL, SHOWING NOSTRIL, PHARYNX, LARYNX 



AND RELATED STRUCTURES. 



292 



