‘Bricks-and-mortar’ model of the stratum corneum – a sophisticated laminated covering
Cosmetics Business is asking personal care industry experts to answer the cosmetics world’s big questions. Here experts discuss the stratum corneum, and how important it is for our overall skin health.
Over to the experts...
Steve Barton
Steve Barton, Director, Skin Thinking Ltd
Stratum corneum (SC) is the outermost part of 'you', comprising an amazingly thin layer of cells – corneocytes.
SC forms as a result of controlled cell division and maturation in the epidermis below; the epidermis lies atop the dermis, a source of nutrients and additional protection.
Human skin is ~1mm thick but SC, though only ~0.015mm thick, is highly organised as layers of flat, roughly hexagonal shaped corneocytes, each one ~0.030mm across and ~0.001mm thick.
Each cell contains keratin, filaggrin and various breakdown products (natural moisturising factors, NMF), within a tough cornified cell wall.
Corneocytes are bound together by tough junctions (corneodesmosomes) and separated by specialised lipids: ceramides, fatty acids and sterols. SC also has its own protective antioxidants.
This tough 'bricks-and-mortar' organisation supports SC