9 o 



RESPIRATION 



Beginning with the larynx, it is seen that the cartilages of which it 

 is composed are sufficiently rigid and unyielding to resist the pressure 

 produced by any inspiratory effort. Across its opening are the vocal 

 chords, which are four in number and have a direction from before 

 backward. The two superior are called the false vocal chords, because 

 they are not concerned in the production of the voice. The two inferior 



Fig. 28. Trachea and bronchial tubes (Sappey). 



I, 2, larynx ; 3, 3, trachea ; 4, bifurcation of the trachea ; 5, right bronchus ; 6, left bronchus ; 7, bron- 

 chial division to the upper lobe of the right lung; 8, division to the middle lobe; 9, division to the 

 lower lobe; 10, division to the upper lobe of the left lung; n, division to the lower lobe; 12, 12, 12, 

 12, ultimate ramifications of the bronchia; 13, 13, 13, 13, lungs, represented in contour; 14, 14, summit 

 of the lungs; 15, 15, base of the lungs. 



are the true vocal chords. They are ligamentous bands covered with 

 folds of mucous membrane, which is quite thick on the superior chords 

 and very thin and delicate on the true vocal chords. These bands are 

 attached anteriorly to a fixed point between the thyroid cartilages, and 

 posteriorly, to the movable arytenoid cartilages. Air is admitted to the 

 trachea through an opening between the chords, which is called the rima 

 glottidis. Little muscles, arising from the thyroid and cricoid and at- 



