Corneocytes

Predominant "cell population" of the stratum corneum. The corneocyte is embedded in a matrix of lipids and water-binding "moisturizing" factors according to the brick and mortar principle. Basically, the structure of the stratum corneum can be described as a two-compartment model:

• Corneocytes (cornified (apoptotic) keratinocytes)
• Intercorneocyte lamellar lipid layers.

Corneocytes are dead cell formations which are formed from living keratinocytes through a defined apoptosis program. In their entirety they form the stratum corneum. This layer consisting of keratin has an important function as permeability barrier of the organism. Essential for the development of an intact barrier function is the presence of lipids in the corresponding composition and their specific structural organisation. The lipids consist in approximately equal proportions of ceramides, cholesterol and triglycerides as well as free fatty acids.