The dermis is made up of connective tissue: a gelatinous structure formed from connective fibres, which acts as a liaison and support system between the various tissues and cells. The dermis contains between 20 and 40% of the body’s total water content and is between 10 and 40 times thicker than the epidermis.
It consists of 3 layers:
- The papillary dermis
- The reticular dermis
- The deep dermis
In the heart of the dermis, fibroblasts form a tri-dimensional meshing between the different protein fibres which, in turn, provides support for the epidermis and ensures the skin’s mechanical properties are maintained. The dermis gives the skin its resistance (Collagen), supports the epidermis and ensures its elasticity (Elastin). It also acts as a water reservoir through the proteoglycan gel.
Highly vascular, it provides the skin with energy and nutriments. In this way, it plays a vital role in the skin’s healing and heat regulating processes.
Composition of the Dermis
It is largely made up of:
- Fibroblasts: the predominant cells in the dermis. They synthesize the collagen, elastin and glycoprotein structural fibres. The destruction of these fibres automatically occurs with age. Their numbers drop by half between the ages of 20 and 80.
- Collagen: inelastic fibre and principle structural protein. It is the predominant component of connective tissue and provides support for surrounding tissue. It gives the skin its resilience and firmness. Collagen fibres trap water and thus contribute to the skin’s hydration.
- Elastin: elastic protein fibre that has the ability to stretch and contract thus providing tissues with suppleness and elasticity.
- Extracellular matrix or ground substance in which the connective fibres bathe. It ensures their cohesion and consists of water and proteins = proteoglycane gel (glycoproteins) or mucopolysaccharides from GAG Glycoaminoglycans, the main component of which is hyaluronic acid: sugar-based molecules whose job is to capture water in the dermis.