The skin is basically divided into epidermis, dermis and subcutis. The most superficial layer, the epidermis, is further differentiated into the Strata corneum, lucidum, granulosum, spinosum et basale. The stratum corneum develops more strongly under stress, especially on the palm of the hand and sole of the foot. In the stratum basale, melanocytes come to rest, whose activity determines the tanning type much more than their number. Below the epidermis is the dermis, which is composed of the Strata reticulare et papillare. Here, for example, sweat and sebaceous glands and hair follicles are located. The subcutis serves, among other things, for heat insulation and the detection of vibratory stimuli. The skin is on average 1.5 to 4 mm thick and can weigh up to 10 kg. It is therefore both the largest and heaviest organ in the human body.
The epidermis can be divided into 4 or 5 individual layers. In addition to the Strata basale et corneum described above, the other sections can also be classified more precisely. In the Stratum spinosum, the socalled "prickle cell layer", immunocompetent defense cells (Langerhans cells) can be found, among others. Furthermore, the Stratum granulosum carries socalled "Odland bodies", whose secretion counteracts the drying out of the epidermis. The Stratum lucidum is usually only visible in strongly keratinized body parts.