Skin and its functions
Skin, or cutaneous membrane, is one of the principal epithelial membranes of the body. It covers its entire surface, which is an area of around 2 square meters. The skin and its appendages (sweat and oil glands, hair, and nails), are collectively called the integumentary system.
The integumentary system performs various functions, which protective is the most important one. It insulates inner body organs and protects the entire body from mechanical damage, chemical damage, thermal damage, ultraviolet radiation, and microbes. The structure of the skin prevents water loss from the surface of the body. Moreover, the skin’s capillary network and sweat glands control heat loss. Finally, the skin acts as a small chemical plant - it synthesizes several proteins for the immune system and produces vitamin D.