OBSERVATIONS OF THE PULMONARY CAPILLARY AND ALVEOLAR CASTS UNDER THE SCANNING ELECTRON MICROSCOPE / 解剖学报

ABSTRACT

Three fresh lungs removed from three male adult dogs were injected with ABS. This material was injected into each lobe of the lung through the pulmonary artery and bronchus simultaneously. The pressure was maintained between 200～280 mmHg. The injected specimens were digested in 20～50％ HCl and peptic solutions for 7～10 days. A part of the cast replicas of the lungs was taken off and gilded with EIKO IB-3. Under SEM (HITACHIS～450) the specimens thus prepared were observed. The chief findings were as followsScanning electron micrographs of the injected vascular system presented a clear, three-dimensional picture of extensive capillary networks around the individual alveoli. In the septa between alveoli the capillary networks appeared to be a single layer. These networks looked like pentagonal or hexagonal rings; the meshes in between them were smaller than the vessels themselves.The capillaries observed here in the scanning stereopicture belonged to the category of the alvioli cappilary of the subpleura; the meshes of which were larger than those of other parts.Because the numerous alveoli and capillary networks surrounding the alveoli were filled with the ABS, the position and the shape of the capillary networks can be seen very clearly.The lumen of the alveoli were polyhedron in shape, various in sizes and smooth in contour. Many imprints of the alveolar type Ⅱ cell nuclei existed on the surface. The bridge formation between alveoli were really interalveolar pores; their number and diameter varied. The function of the interalveolar pores was briefly considered in this paper.