ABSTRACT
Skin is an extraordinary structure absolutely dependent on this 1.7 m2 of barrier separating the potentially harmful external environment from the body’s vulnerable interior. It is a composite of several types of tissue that have evolved to work in harmony, one with the other, each of which is modified regionally to serve a different function. The skin surface is the delineation between living processes and the potentially injurious outside world and has not only a symbolic importance because of this, but also the important task of preventing and controlling interaction between the outside and the constant and vulnerable inside. Its 1.7 m2 area is modified regionally to enable it to better perform particular functions. The epidermis contains keratinocytes mainly, but also non-keratinocytes – melanocytes and Langerhans cells, both of which possess dendrites. This cellular structure is some three to five cell layers thick, on average, 35–50 µm thick in absolute terms.
