THE RELATION BETWEEN BRONCHIAL AND PULMONARY CIRCULATIONS IN THE HUMAN LUNG, INVESTIGATED BY RADIOPAQUE INJECTIONS

¹ The Department of Physiology, University of Birmingham

1. The systemic arterial vessels reaching the human lungs and visceral pleura have been shown to be independent of the pulmonary vessels by their injection from the aorta with a radiopaque material which does not traverse capillaries.

2. Vessels have been distended by radiopaque material to 14 µ in diameter, without passage of the material into the pulmonary circulation, showing that if anastomoses between the pulmonary and bronchial systems are present, they exist in the region of capillaries or by means of arterioles and venules less than 14 µ in diameter when fixed, i.e. they form a physiological connection and in this sense are not true anatomical anastomoses.

3. The relations of the systemic vascular distribution in the human lung to various lung structures, are discussed and found to be analogous to those in the Dog except in the blood supply of the visceral pleura.

4. In Man, the visceral pleural systemic blood supply serves not only the pleura, but over the medial surface, also the pleural nerve trunks.