On diseases of the chest : being contributions to their clinical history, pathology, and treatment / by A.T.H. Waters.

Date:
1868
Catalogue details

Licence: Public Domain Mark

Credit: On diseases of the chest : being contributions to their clinical history, pathology, and treatment / by A.T.H. Waters. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

    45/494 (page 15)
    From the arrangement I have described, it will be seen that the pulmonary plexus is, for the most part, exposed to the air on both sides, a condition which is of the utmost importance with reference to the proper aeration of the blood. As the vessels lie in the walls of the air-sacs, and in the septa between the alveoli, the air circulates on both sides of them, in consequence of a single layer alone existing. This statement applies as a general rule, but if the opinion I have expressed above with reference to the external sacs of the lobulette be correct, then an exception exists to the double exposure of each blood-giobule; and, moreover, there is another exception, viz., in the vessels which are placed at the fundus of those sacs which are situated at the periphery of the lobules. It is clear that when the fundus rests on the sheath which invests the lobule, and which is separated fi'om the sheath of the adjoining one by areolar tissue, or rests on the pleura, the vessels which are spread out on the alveoli of the fundus can only be exposed to the air on one side. It appears, therefore, from these remarks, that some portion of the pulmonary plexus is not so arranged that its capillaries shall have air circulating on both sides of them, but that by far the greater portion of it is thus placed. It may further,be remarked that, in all proba- bility, before the blood reaches the fundus of the sacs I have alluded to, or even the periphery of the lobulettes, it has passed over other alveoli, and been aerated in them, and is, in fact, ready to be taken up by the pul- monary veins. The branches of the pulmonary artery, which are dis- tributed to the bronchial alveoli, anastomose freely at the mouths of the air-sacs with the capillary plexus formed in the walls of the sacs. The vessels distributed to the sacs themselves, and the plexus arising from them, pass