THE NERVO-VASCULAR SUPPLY OP THE LUNGS. 481 



nervo-vascular mechanism of the lungs and the respiratory 

 process: 



1. The nervo-vascular functional mechanism of the lungs 

 consists of two autonomous, though correlated, systems: the re- 

 spiratory and bronchial. 



2. The respiratory nervo-vascular system is composed of: 



(a) The pulmonary lobules, in the walls of which the blood 

 is oxygenated. 



(b) The pulmonary artery and its subdivisions, which bring 

 venous blood, adrenal secretion, and granules (3 to the capillaries 

 of the lobules. 



(c) The pulmonary venules and veins, which return the 

 arterialized blood to the heart. 



(d) The general motor nerves and plexuses (sympathetic), 

 which govern the functions of the foregoing structures and the vaso- 

 constriction of all vessels of the pneumo-respiratory system. 



8. The bronchial nervo-vascular system is composed of: 



(a) The bronchial arteries, which, by their oxidizing sub- 

 stance, sustain functional energy and metabolism in: (I) the in- 

 terlobular cellular tissue and its lymphatic vessels and glands, the 

 blood thus used passing to the vence azygos, by the bronchial veins, 

 thence to the superior vena cava; (II) the bronchi, the terminal 

 ramifications of which only reach to the exterior of the lobules, but 

 anastomose with the pulmonary capillaries of the latter. 



(b) Vagal nerves and plexuses, which supply sensation to the 

 bronchial mucous membrane, incite and govern its secretion and 

 the vasoconstriction of all vessels of the bronchial system. 



4- The process through which functional energy is supplied 

 to the lobular structures (epithelium, basement membrane, and 

 vascular walls of the lobules) to compensate for the absence of 

 oxygen in the blood brought to them by the pulmonary artery is 

 as follows: The oxidizing substance in the blood of the bronchial 

 terminal branches which anastomose with the lobular capillaries, 

 meets the granules ft contained in the blood of the latter; oxida- 

 tion of the granules ensuing, functional energy is liberated, as it is 

 elsewhere in the organism. 



5. The functional oxidation process through which the right 

 heart is supplied with mechanical energy is repeated in the pulmo- 

 nary lobules, and there is some ground for the belief that the con- 



