Figure 6.

Electron micrographs of ultrathin sections of the hilus region (a–c) and the lung periphery (d–f) from control (a, d, g), NID1^–/– (b, e, h), and NID2^–/– (c, f, i) mice. The lamina elastica interna (LEI) is marked by asterisks (a–c). The alveolar BM is recognized as a homogeneous layer of extracellular matrix (indicated by asterisks) between the epithelial lining of the alveoli and the endothelia cells of the capillaries of the interalveolar septa (g–i). The arrows mark the different cell types; E, erythrocyte; EC, endothelial cell; EM(II), second elastic membrane; P(I), pneumocyte type I; P(V), pneumocyte type V; SMC, smooth muscle cell. Scale bars = 5 µm (a–c); = 1.75 µm (d–f); = 0.4 µm (g–i).