Answer
Keratinocytes are derived by cell division from stem ells in the stratum basale ( or S. germinativum ) at the bottom of the epidermis. Layers of the fibrous protein keratin are laid down in these cells as they are pushed towards the surface by the continuous cell division of the cells in the stratum basalis. In moving up, the keratinocytes which start as normal active metabolising cells with cell organelles and ovoid nucleus, get further and further from the nutrient blood supply of the dermal vascular network. The predictable consequences are that the cells lose moisture;their organelles disintegrate; their metabolism is impaired ;nuclei flatten and cease to function. The end result of this process of apoptosis is that the cells arrive at the upper layers as dead flattened "scales" of the protein keratin.
Work Step by Step
Keratinization is beneficial to the body because keratin is a tough protein that keeps in the body's moisture and protects the skin from damage by abrasion, chemicals , radiation and microbes.
