The bronchial vascular system in the dog

Abstract

The distribution of the bronchial arteries (the vasa nutritia of Reisseissen) within the lung has been investigated by many anatomists but, beyond our knowledge that they are nutritional vessels to the bronchial tree (Reisseissen and Sömmering, 1808; Reisseissen, 1808, 1822 ; Luschka, 1863; Königstein, 1903), little is known of their significance for the maintenance of the normal functions of the lungs. At the moment their chief interest lies in the number of reports describing the changes in the bronchial blood vessels resulting from interference with the pulmonary vascular system and from lesions in the lungs. Two years ago Professor E. B. Verney and one of us (I. de B. D.) were conducting experiments in this laboratory which involved the separation of the pulmonary from the systemic circulation in the dog, the two systems being perfused by separate pumps. In one experiment it appeared that blood was being transferred from the aorta to the left auricle through the bronchial vascular system. It became desirable, therefore, to inquire into the conditions which govern the bronchial blood supply. At an early stage in this inquiry it was evident that, owing to the variations in the origin of the bronchial arteries, a study of the gross and minute anatomy of the bronchial vascular system in each perfusion experiment would be necessary if anything approaching a correct interpretation of our results was to be expected. As a preliminary investigation to our perfusion experiments, we have examined the bronchial vascular system in a number of animals and the results form the subject of this paper. In it are also incorporated the anatomical findings on the perfused lungs used for physiological investigations. We have concentrated our efforts on two main issues: the first, the arrangement of the bronchial arteries and veins with a view to setting up apparatus for perfusion of the bronchial arteries and the collection of the blood from the bronchial veins ; the second, an enquiry into possible arterial and venous communications between the bronchial and pulmonary vascular systems. It is clear that if arterial anastomotic channels exist between the two systems it will not be possible to separate completely the arterial blood of each.