Abstract
Morphological details of the human bronchial circulation were investigated using autopsied lungs which were macroscopically normal. The bronchial artery was injected with orange silicone rubber at 130cmH_2O hydrostatic pressure. The pulmonary artery was injected at 40cmH_2O hydrostatic pressure with yellow silicone rubber containing carbon particles 40 microns in diameter which could not pass through alveolar capillaries. Intrapulmonary bronchial arteries did not run along bronchial veins but often crossed each other. Bronchial veins immediately joined pulmonary veins after leaving the bronchial wall. In bronchial arteries of segmental or subsegmental bronchi mixture of orange silicone rubber and yellow silicone rubber containing carbon particles 40 microns in diameter was observed. This findings suggests the presence of precapillary anastomosis larger than 40 microns in diameter between the bronchial artery and the pulmonary artery. This anastomosis is considered to be located in the region of segmental or subsegmental bronchi.
