Figure 14-7.

Histologic Features of Glial Cells, Ventral Gray Horn, Spinal Cord, Horse.

A neuronal cell body and its processes are in the center of the illustration. To the inexperienced, identifying specific types of glial cells in H&E-stained histologic sections can be challenging. Astrocytes (arrows) have larger vesicular nuclei (dispersed chromatin), and the cell membrane and cytoplasm are rarely seen in nondiseased conditions. Thus these nuclei just seem to “sit” in the midst of the neuropil. The majority of nuclei in the neuropil here are astrocytic. Oligodendroglial cells (arrowheads) have smaller and dense round nuclei (condensed chromatin) often surrounded by a clear zone indicative of cell cytoplasm and a cell membrane. Oligodendroglial cells in gray matter are called perineuronal satellite cells; those in white matter are called interfascicular oligodendrocytes. Microglial cells can be difficult to identify in H&E-stained sections of the central nervous system (CNS) but are often identified by their small, dense elongated nuclei (dashed arrow). The light pink homogeneous tissue distributed in large quantities between these cell types is the neuropil. V, Blood vessels. H&E stain.

(Courtesy Dr. J.F. Zachary, College of Veterinary Medicine, University of Illinois.)