Content deleted Content added
tag Unreferenced, add Ref section |
m WikiCleaner 0.75 - Repairing link to disambiguation page - You can help! |
||
Line 1:
{{Unreferenced|date=December 2007}}
Cutaneous structures arise from the [[Epidermis (skin)|epidermis]] and include a variety of features such as hair, feathers, claws and nails.
During embryogenesis, the epidermis splits into two layers: the periderm (which is lost) and the [[Stratum germinativum|basal layer]]. The basal layer is a [[stem cell]] layer and through asymmetrical divisions, becomes the source of skin cells throughout life. It is maintained as a stem cell layer through an [[autocrine]] signal, [[Transforming growth factor|TGF-a]], and through [[paracrine]] signal FGF7 aka [[keratinocyte growth factor]] (KGF) produced by the dermis below the basal cells. In mice, over-expression of these factors leads to an overproduction of granule cells and thick skin.
| |||