The epidermis, as the most external layer that can be seen and touched, protect us from toxins, bacteria and fluid losses. It is formed by five sublayers of cells called keranocytes. These cells, produced in the deepest basal layer, migrate to the skin surface where they mature and suffer from several changes. This process, known as keratinization makes each sublayer different. The cells of the horny layer are connected by epidermic lipids. These lipids are essential for skin health: they create their protective barrier and retain moisture. When there is a lack of lipids, the skin may become dry, and can be felt tight and rough.
The epidermis is covered by a emulsion of water and lipids (fats) known as hydrolipidic film. This film is maintained by secretions of sebaceous or sweat glands that contributes to maintain flexible skin, acting as additional barrier against bacteria and molds.
The dermis is the middle layer in the skin, being thick, elastic but firm, composed of two sublayers:
- Bottom layer (reticular stratum): Thick and deep area, that converge with the subcutis in liquid form;
- Upper layer (papillary layer): Establishes a defined confluence with epidermis in wave shape,
The main structural components of the dermis are the collagen and elastin, connective tissues that confer strength and flexibility, being vital components in healthy and youthful appearance of the skin. These fibres are impregnated with a gel-like substance (contains hyaluronic acid) that has a great capacity to retain the water and to contribute to keep skin volume.
Our current way of life and external factors such us sun and change of temperature impact on natural collagen and elastin level and on the surrounding structure.As long as we age, our natural production of collagen and elastindecline and decrease skin´s ability to retain water. The skin becomes less toned and wrinkles appeared.
The inner layer of the skin stores energy and acts as a pad and body insulator. It is mainly formed by:
- Fat cells (adipocytes): Aggregated and forming groups (padtypes);
- Special fibres of collagen (tissue septa or limits): Spongy and loose connective tissue that holds together fat cells;
- Blood vessels.