Don W. Fawcett (2011) CIL:10888, Annelida, glial cell (sensu Nematoda and Protostomia). CIL. Dataset

The early days of electron microscopy provided the first views of cell ultrastructure. This electron micrograph shows the plasma membranes of two closely apposed glial cells from the central nervous system of the annelid Aphrodite (commonly known as a Sea mouse) obtained from a thin section. EM images of cell membranes, such as this one, suggested a tri-laminar structure to the membrane, detected as two thin dark lines separated by a layer of lighter intensity. The ability to visualize previously unseen ultrastructural elements of the cell, like cell membranes, fueled debate about their composition, organization, and biological function. The distance of the intercellular cleft between the two membranes is 15nm. This is Figure 1 from Chapter 1 (Cell Surface) of 'The Cell, 2nd Ed.' by Don W. Fawcett M.D. A PDF copy of the accompanying chapter is available on the ASCB's BioEDUCATE website.

电子显微镜的早期阶段为细胞超微结构的首次观察提供了可能。本电子显微图像展示了来自环节动物海兔（俗称海鼠）中枢神经系统的紧密相邻的两胶质细胞的质膜，图像源自薄片。此类细胞膜图像（如本例所示）提示了膜的三角层结构，表现为两条细密的暗线被一层亮度较低的层隔开。可视化细胞（如细胞膜）先前未曾见过的超微结构元素，激起了关于其组成、组织和生物学功能的辩论。两个质膜之间的细胞间隙距离为15纳米。此图像为《细胞》第2版第一章（细胞表面）中的图1，由Don W. Fawcett M.D.所著。该章节的PDF副本可在ASCB的BioEDUCATE网站上获取。