Epidermis

The epidermis (the strongest layer) forms the upper protective barrier of the skin. The outermost part or the corneal is comprised of millions of dead skin cells, which are shed and continually replaced by living cells (epidermal keratinocytes) that originate from the basal or germinative layer. Did you know that 90% of household dust is dead skin cells? Keratinocytes contain structural protein (keratin) and become progressively flattened as they advance upward from the basal layer to the corneal layer. This advancement takes proximately 14 days.

Melanocytes, among the basal cells of the epidermis, produce melanin, the protective pigment responsible for skin colour.

Melanocytes are stimulated by sunlight, therefore produce sufficient melanin to protect the skin against harmful ultra violet radiation. Vitamin D production in the skin is dependent on UVR (ultra violet radiation) penetrating epidermal cells to reach a particular chemical compound (ergosterol), which is important in the prevention of rickets and softening of the bones in elderly people.

Another type of cell within the epidermis is the Langerhans. Found in the middle section of the epidermis, these cells perform an immunological attack on foreign substances that penetrate the skin.