EESPIEATOEY ORGANS 



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where a hard swelhng may be felt, called the Adam's 

 apple. This is the larynx, or voice box, and is on the top 

 of the windpipe. The trachea itself may be felt below this 

 projection and recognised by the rings of cartilage which 

 encircle it and prevent its collapse as the air is sucked in. 

 The entrance to the larynx and trachea is guarded by a 

 lid called the epiglottis which is always open to admit 



Bronchial 



tubes. 



Fig. 146 — Diagram of tracliea and connections. 



air, except in the act of swallowing, when it closes to pro- 

 tect the tube from entrance of food. 



At its lower end the trachea splits into two branch 

 tubes, or bronchi, which, in turn, split into smaller and 



