[Morphodynamic analysis of lung microcirculation (a supravital morphological study)]

Using the system of contact optics, the circulation (microcirculation) was studied in the lungs of 15 adult Wistar rats during the normal physiological location of the organs inside the thorax. A 4x4 mm "window" was made in the tissues of the thorax of an anaesthetized rat, through which the pleura was incised, resulting in the lung collapse. The lung was filled with oxygen or hypoxic gas mixture under the pressure of 10-15 cm of water column through a tracheotomic cannula. Then the lung was brought in contact with the contact objective aperture (1.7 mm in diameter). Each alveolus was supposed earlier to be supplied with blood via a thinnest (5-10 microm in diameter) lung arteriole. The present study has shown that there exists a system of wide (20-30 microm in diameter and larger) microvessels, which run between the alveoli. These microvessels surround each alveolus, practically, from all the sides. In such a manner each alveolus is supplied by a maximal amount of blood. Such a structure of the lung circulation system accounts for a great blood flow through the lungs (up to 6 1 per minute in humans) and a rapid saturation of the blood with oxygen.