The human skin consists of three layers: the top layer of keratinocytes, the middle layer of epidermis, and the bottom layer of dermis. Keratinocytes are the upper cells that protect the skin from environmental influences. The epidermis serves as a supporting layer, while the dermis provides nourishment to the skin and serves as the foundation for all three layers.

Exposure to ultraviolet rays damages the skin’s cells (fibroblasts), which produce fibers (collagen and elastin). As a result, the skin loses its elasticity.