The skin: its functions and structure
Titanium dioxide and silver nanoparticles

The skin is an important protective organ, representing a weight of around 5 kg and a surface area of 2 m ² for an adult. Its thickness varies widely: from 0.5 mm at the eyelids to 4 to 5 mm at the top of the back. Our skin (figure 1 ) is made up of several layers: on the surface is the epidermis, followed by the dermis and hypodermis. A number of accessory organs, such as hair, nails, sebaceous glands and sweat glands, are inserted into the skin.