Dermis: Organization and Matrix Week 16

Papilliary and reticular dermis regions begin to be established

These regions are distinguished by the size and orientation of their collagen fibrils. The major collagen type secreted is still type III.

Huge periderm cell blebs project into the amnionic fluid, representing the pinnacle of periderm development. A blood vessel and parallel nerve fiber in the dermis cross the image diagonally. Note how much more space (how much less cellular) there is between the dermal cells in the lower dermis compared to the region just below the dermal-epidermal junction. This image shows the beginnings of dermal organization to papillary and reticular layers.