Skin Health

Skin Histology

The epidermis or cuticle (scarf-skin) is non-vascular, and consist of stratified epithelium. It is accurately molded on the papillary layer f the derma. It forms a defensive covering to the surface of the true skin, and limits the evaporation of watery vapor from its free surface. It varies in thickness in different parts. In some situations, as in the palms of the hands and soles of the feet, it is thick, hard and horny in texture. This may be partly due to the fact that these parts are exposed to intermittent pressure, but that this is not the only cause is proved by the fact that the conditions exist to a very considerable extent at birth. The more superficial layer of cells, called the horny layer (stratum corneum), may be separated by maceration from deeper layers, which are called the rate mucosum or atratum Malpighii, and which consist of several layer of differently shaped cells. The free surface of the epidermis is marked by a network of linear furrows of variable size, marking out the surface into number of spaces of polygonal or lozenge-shaped form. Some of this furrow are large, as opposite the textures of the joints, and correspond to the folds in the dermis produced by their movements.

In other situations, as upon the back of the hand, they are exceedingly fine, and intersect one another at various angles; upon the palmar surface of the hand and fingers and upon the sole of the foot these lines are very distinct and are disposal in curves.

They depend upon the large size and peculiar arrangement of the papillae upon which the epidermis is placed. The deep surface of the epidermis is accurately molded upon the papillary layer of the dermis, each papilla being invested by its epidemic sheath; so that when this layer is removed by maceration, it presents on its under surface a number of pits or depressions corresponding to the elevations in the papillae, as well as the ridges left in the intervals between them. Fine tubular prolongations are continued from this layer into the ducts of the sudoriferous and sebaceous glands.

posted by Margi @ 6:29 PM