Find a region near the developing spinal cord. You should be able to locate tissue similar to Figure 3-1 on page 15 of your atlas. The word mesenchyme means CT that has not yet differentiated into discernable end cells, such as a bone cell (osteocyte) or cartilage cell (chondrocyte). The mesenchymal cells in this pig embryo are largely undifferentiated. Some have already become blood vessels and blood cells, but most remain undifferentiated and star-shaped (stellate). There are many mitotic figures within this tissue. Mesenchymal CT can arise from any of the germ layers associated with embryo development.
Tooth pulp is one of the few places in the post natal mammalian body that retains a mesenchymal appearance. The cells are stellate-shaped, with a considerable amount of intercellular material. In this preparation, cell borders sometimes are difficult to observe, and, due to the thinness of this section, the stellate shape of cells may be more difficult to appreciate.Slide 17 is of 5 µm thick, neonatal rodent head
A more typical version of tooth pulp. The increased section thickness contains more of each cell. Hence, you can resolve the long cells. Masson's trichrome stain turns collagens blue or green. This slide demonstrates that the mucoid ground substance in tooth pulp is not sufficiently collagenous to show distinct collagen bundles.
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On to irregular and regular CT |