Outer Skin (Epidermis)

The epidermis, which in some places is only paper-thin, is formed of so-called keratinizing squamous epithelium and consists of 5 layers. The bottom layer, the germ or basal cell layer (stratum germinativum, stratum basale), constantly produces new cells that gradually move up to the surface over a period of 3 to 4 weeks and become increasingly flatter. These newly formed spinous or prickle cells are transformed into granular cells, the shiny cells of the stratum lucidum (only on the hands and feet) and the horny cells, which have no nucleus. Ultimately, these cells lie as horny scales on the surface of the skin, from where they are then shed. Each layer of cells is at the same stage of transformation. Altogether, most of the cells in the epidermis are in the process of keratinizing (becoming horny). These cells (keratinocytes) account for up to 95 % of the cells in the epidermis. In the deeper part of the epidermis, there are …

True Skin (Dermis)

The dermis is the layer that gives the skin its elasticity, and it contains the blood vessels, the adnexae of the skin (sebaceous glands, sweat and scent glands, hair and nails), and the nerves and sensory organs of the skin. The dermis is located underneath the epidermis and the connecting basement membrane, and provides the foundation for the outer skin or epidermis. It consists primarily of ground substance and a dense network of bundles of connective tissue (collagen fibrils) and elastic fibres. Collagen accounts for about 18 to 30 % of the volume of the dermis. The collagen fibrils allow the skin to stretch, and the elastic fibres give it its resilience. The skin is elastic and, depending on region, can stretch by between 10 and 50 %. When the skin is pressed in, the ground substance is displaced between the collagen fibrils. The papillary dermis (stratum papillare) forms the upper zone of the dermis and consists of loose connective …