The I.P. Pavlov Institute of Physiology, Russian Academy of Sciences, Sankt Petersburg, Russia.
Adv Exp Med Biol. 2013;756:197-201. doi: 10.1007/978-94-007-4549-0_25.
In this study we investigated microcirculation in the lungs in their in situ physiological location inside the thorax. The study was performed with the use of a system of contact optics. A 'window', 4 × 4 mm in size, was made in thorax tissues and pleura of an anaesthetized rat. The lung collapsed and then was filled with oxygen or hypoxic gas mixture under the pressure of 10-15 cm H(2)O through a tracheostomic canula. This almost excluded the respiratory movements of the lung. Then, the lung was brought in contact with a lens (1.7 mm aperture). We showed that there is a whole system of wide microvessels (20-30 μm in diameter) which run between the alveoli; the finding contradicting the hitherto notion that each alveolus is supplied with blood via the thinnest (5-10 μm in diameter) lung arterioles. The microvessels we visualized surround each alveolus almost from all sides. In this way, each alveolus receives a maximum amount of blood. Such a structure of lung circulation accounts for a substantial blood flow through the lungs (up to 6 l per min in humans) and for a rapid saturation of the blood with oxygen (about 100 ml per second). The alveoli saturate the blood with oxygen and subsequently the microvessels form the lung veins entering the left auricle. The photographs and video films of the alveoli at a high magnification were presented, demonstrate the special features of the structure and circulation in the alveoli. The plausible mechanisms of rapid saturation of the blood with oxygen are discussed.
在这项研究中，我们研究了胸腔内原位肺微循环。研究使用接触光学系统进行。在麻醉大鼠的胸腔组织和胸膜上制作一个 4×4 毫米大小的“窗口”。通过气管造口插管在压力为 10-15 厘米 H₂O 下使肺塌陷，然后用氧气或低氧混合气体填充。这几乎排除了肺的呼吸运动。然后，将肺与透镜（孔径 1.7 毫米）接触。我们表明，存在一个广泛的微血管系统（直径 20-30 微米），它们在肺泡之间运行；这一发现与迄今为止的观点相矛盾，即每个肺泡通过最细的（直径 5-10 微米）肺小动脉供血。我们观察到的微血管几乎从各个方向包围每个肺泡。这样，每个肺泡接收最大量的血液。这种肺循环结构解释了大量的血液流经肺部（在人类中高达 6 升/分钟），以及血液快速与氧气饱和（每秒约 100 毫升）。肺泡使血液与氧气饱和，随后微血管形成进入左心房的肺静脉。呈现了高倍放大的肺泡的照片和视频，展示了肺泡结构和循环的特殊特征。讨论了血液快速与氧气饱和的可能机制。
