Chap. XIII] 



SUMMARY 



251 



Voice . 



Trachea 



Bronchi 



Lungs 



Produced by vibrations of vocal cords. 



( Pharynx. 

 Resonating cavities < Mouth. 



I Nasal cavities. 

 Lower pitch of male voice is due to greater length of vocal 



cords. 

 Fibrous and muscular tube, 4^ in. long. 

 Strengthened by C-shaped f Complete in front, 

 hoops of cartilage I Incomplete behind. 



In front of oesophagus. 

 Extends from larynx to third thoracic vertebra, where it 



divides into two bronchi. 

 Right and left — structure similar to trachea. 



r 1 in. long. 

 Right I f in. wide. 



I Almost horizontal. 

 [■ 2 in. long. 

 Left < f in. wide. 



I Almost vertical. 

 Divide into innumerable bronchial tubes or bronchioles. 

 Location — Occupy all of the cavity of the thorax that is 

 not taken up by the heart, blood-vessels, lymphatics, 

 and oesophagus. 



Outer surface convex to fit in concave 



cavity. 

 Base concave to fit over convex diaphragm. 

 > Apex rises half an inch above the clavicle. 

 Hilum or depression on inner surface 

 gives passage to bronchi, blood-vessels, 

 IjTiiphatics, and nerves, 

 f Three lobes — larger, heavier, broader, 

 I shorter. 



/ Two lobes — smaller, narrower, longer, 

 I front border deeply indented. 

 ' Hollow, spongy organs. Consist of bron- 

 chial tubes — infundibula — alveoli, also 

 blood-vessels, lymphatics, and nerves 

 held together by connective tissues. 

 Blood for aeration. 

 Accompany bronchial tubes. 

 Pulmonary J Plexus of capillaries around 

 artery alveoli. 



Returned by pulmonary 

 veins. 

 Bronchial arteries — supply lung substance. 



1. Branches from the sympathetic system. 



2. Branches from the pneumogastric. 



Cone-shaped 

 organs 



Right 



Left 



Anatomy 



Blood-vessels 



Nerves 



