Methacrylate-embedded E20 embryo in the coronal plane (anterior)
Figure 121. This anterior coronal slice cuts through the main olfactory bulb of a normal E20 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 is the dense innermost layer, 2) the less dense SVZ is difficult to distinguish from the 4) forming granule cell layer, 5) spindle-shaped cells fill the internal plexiform layer, 6) mitral cells with dense cytoplasm are arrayed in contiguous clusters where cells enter from the internal plexiform layer and other leave to populate the external plexiform 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 fibers.