Issue 21 — October 1999

Protection against enviromental influences The horny layer forms a barrier between the body and its surroundings. It prevents the body from drying out, and protects it from environmental influences. The horny layer is a closely intermeshed system of horny cells (corneocytes) and a fat system (lipid system). The horny cells are conected by desmosomes (protein structures). As the desmosomes undergo degradation, the horny cells are shed as scales of skin.

Moreover, the horny cells are held together by the lipid system, which functions as a cement. Scientists have studied this fatty structure more closely. The lipid layers contain a number of main components: fatty acids, cholesterol, triglycerides and ceramides. Together with water, these four main components form the lamellar (layered) gel-like lipid system of the horny layer.

Picture 1 Cell division occurs in the innermost layer layer of the epidermis (stratum basale). As a result, new cells continuously migrate towards the surface of the skin and keratinize.

Picture 2 The horny layer of the skin is a closely meshed system of horny cells (corneocytes) and lipid layers.

Picture 3 The lipid system between the horny cells serves as cement and as a skin barrier. Together with water, its four main components — fatty acids, triglycerides, ceramides and cholesterol — form the lamellar liquid crystalline lipid system.

Pictures 1 - 3: in view of tomorrow 6 Research and Development at Henkel