Morphological features of blood circulation in the guinea pig lung

The morphology of the lobar artery branches of the guinea pig lung was examined by optical microscopy and by the scanning electron microscope. Our results demonstrate that these branches consistently present a "rosary-like" structure that had been previously observed only occasionally in specimens of various organs from different animals. The function of these "bead-like" structures seems to be that of a control system of the blood flow to the lung alveoli, rather than that of a "pumping heart", as postulated previously by other authors.