About your skin
Our skin’s functions and layers
Our skin protects us from ultra-violet (UV) radiation and dehydration, and is an immunological organ protecting us from infections. It helps control our body temperature through blood circulation and sweating, and also produces vitamin D when in sunlight. Through our nerves, the skin also provides sensations and brings us “in touch” with the external world. Our skin has three layers: epidermis on top, dermis, and beneath these two, the hypodermis or subcutis.
What each layer does
- The epidermal outer layer varies in thickness from 0.04 mm in the eyelids to 1.4 mm on the palms of the hands and soles of the feet. It protects us against bacterial or viral diseases, as well as chemicals and UV radiation and acts as a resistance to forces.
- Under the epidermis, the dermis varies in thickness, from about 0.3 mm in the eyelids to up to 4 mm on the back. It also provides resistance to mechanical stresses and strains, and helps in healing wounds and the immune defence of the skin. Here, blood vessels constrict or dilate to regulate the body temperature. When an injury extends through the epidermis into the dermis, it causes bleeding.
- Underneath both, the fatty tissue of the hypodermis or subcutis keeps the body warm, supplies energy as calories, and protects the underlying tissue from bumps.