The skin is made up of 3 layers: the epidermis on the surface, the dermis and then the hypodermis. All 3 are interdependent but each one has its own role to play.
- The epidermis: “The superficial barrier”
This is the protective layer. Despite not being very thick (several tenths of a mm despite the 4 sub-layers making it up), it is almost impermeable and is constantly being renewed. It is the epidermis which plays the role of protective shield, skin barrier, in particular due to its superficial corneal layer, stratum corneum, and the hydrolipidic film which covers it.
- The dermis: The skin’s “support”, its water reservoir
The dermis is the connective tissue which supports the epidermis, nourishes and moisturises it by diffusion of water. The elastin it contains provides the skin with its elasticity and its suppleness, and the collagen its resistance to tension and traction. This is also the skin’s water reservoir because of the extra-cellular matrix (ECM) composed of glycoaminoglycans including hyaluronic acid. The sebaceous glands (secreting sebum) and the sweat glands (secreting sweat) are also found here.
- The hypodermis: “The shock absorber”
The hypodermis is the deepest layer. It is an adipose tissue with its protective role being to absorb shocks. It is also a heat insulator and the energy reservoir for the skin. Aesthetically speaking, it models the silhouette depending on age and the state of the diet.