Methacrylate-embedded E21 embryo in the coronal plane (anterior)
Figure 134. This anterior coronal slice cuts through the main olfactory bulb of a normal E21 embryo. Cells are sorted in concentric layers around the lumen of the olfactory recess of the lateral ventricle with a large clump of shed cells: 1) the olfactory NEP/ependyma is the dense innermost layer, 2) the less dense SVZ is difficult to distinguish from the 4) forming granule cell layer, 5) spindle-shaped and radial-oriented cells fill the internal plexiform layer, 6) mitral cells with dense cytoplasm are arrayed in a continuous layer, 7) outside of that is the fibrous external plexiform layer with large tufted cells, 8) finally the olfactory nerve layer is full of cells and circular fiber whorls.