Skin: Basic Structure and Function

The document describes the skin as a dynamic and complex structure that plays a crucial role in maintaining internal balance and protecting against external factors. It details the skin's composition, which includes multiple cell types and specific proteins, and its functions such as acting as a barrier, self-repair, thermoregulation, and facilitating immune recognition and tolerance. The skin is made up of the epidermis, which is the primary barrier, and the dermis, which offers structural support, nutrition, and circulation.