A guided tour of our skin

Our skin is an organ in itself. It's composed of several layers: the epidermis, dermis and hypodermis, with each one playing a very different role. Here's the lowdown.

The epidermis

The epidermis is the outermost layer of our skin. It protects us from external harmfull elements (UV, tobacco, pollution, bacteria) and controls permeability (hydration levels). It is an epithelial tissue with three types of cells. Keratinocytes make up 90% of the cells. They synthesize keratin (also present in hair), which protects the epidermis and its permeability. The other two types of cells are melanocytes (skin pigmentation cells which protect from UV) and Langerhans cells, which form part of our immune system. The epidermis itself is divided into five layers: the stratum corneum, the clear layer, the granular layer, the spinous layer and the deep basal layer. Epidermal cells are produced in the basal layer, from where they migrate and transform and specialize as they cross the other layers. On the surface of the epidermis (the skin that we 'see') lies a thin film consisting of lipids, fat and perspiration - the hydrolipidic film. This film fortifies helps in the protection of the skin, defending it from bacteria and preventing the epidermis from drying out. It's on this upper level that active ingredients and nourishing treatments work their wonders. 

The dermis

The dermis is a connective tissue. It consists of two types of cells: fibroblasts, which produce the support fibres elastin and collagen. The dermis is split into two layers: the papillary dermis (rich in nerve endings) and the reticular dermis (a dense mesh of support fibers). The dermis builds the face's 'architectural features', supports the epidermis and protects both blood vessels and nerves. It also contains our hair folicles, sebaceous glands (sebum) and sweat glands. It's in the dermis that you'll find anti-sagging and anti-wrinkle molecules such as hyaluronic acid.

The hypodermis

The hypodermis is the deepest layer of our skin. It essentially consists of fat cells called adipocytes. It creates a cushion between the dermis and our bones, determines the plumpness of our faces and insulates our bodies. It's from the hypodermis that our body draws its energy when we're dieting or fasting.