Carlsen F, Behse F
J Anat. 1980 May;130(Pt 3):545-57.
In a cross section the profile of one or several unmyelinated axons is embraced by profiles of one or several Schwann cells, all surrounded by a basal lamina. Reconstructions demonstrate that this complex structure is the result of overlap and regrouping of contiguous Schwann cells and only to a lesser extent to branching of Schwann cells. More than half the 36 Schwann cells reconstructed did not branch within the 200 micrometer analysed, and one fourth had two branches. Notwithstanding the regrouping of Schwann cells and axons at different levels of the nerve, the number of Schwann cell subunits in a single cross section is a suitable gauge for the number of Schwann cells. The single nucleus is situated midway between the ends of the Schwann cell. The length of the Schwann cells ranges from 220 to somewhat more than 400 micrometer; the thickness is 0x2-0x5 and in the region 2-5 micrometer. Collagen pockets are outpouchings of the Schwann cell which rarely extend over more than 6 micrometer along the Schwann cell; they are spaced at average intervals of 20 micrometer. Outpounchings devoid of collagen pockets have a similar length but occur more rarely. Abnormally dense cytoplasm, when present, is seen throughout the entire length of the Schwann cell.
在横切面上，一个或几个无髓鞘轴突的轮廓被一个或几个施万细胞的轮廓所包围，所有这些都被基膜所包裹。重建结果表明，这种复杂结构是相邻施万细胞重叠和重新组合的结果，而施万细胞分支的作用较小。在分析的200微米范围内，重建的36个施万细胞中一半以上没有分支，四分之一有两个分支。尽管在神经的不同水平上施万细胞和轴突会重新组合，但单个横切面上施万细胞亚单位的数量是衡量施万细胞数量的合适指标。单个细胞核位于施万细胞两端的中间位置。施万细胞的长度范围从220微米到略超过400微米；厚度为0.2 - 0.5微米，在该区域为2 - 5微米。胶原小囊是施万细胞的袋状突出物，很少沿着施万细胞延伸超过6微米；它们的平均间隔为20微米。没有胶原小囊的突出物长度相似，但出现频率较低。异常致密的细胞质如果存在，则在施万细胞的整个长度上都可见。
