ABSTRACT
The human skin, representing the largest organ of the human body, is com-
posed of three layers which differ with respect to the anatomical localization,
structure, properties, and embryological origin (Figure 2.2) [154]. The outer
layer, derived from the ectoderm, is represented by the epidermis. Epidermis
is put in contact with the dermis by the so-called dermo-epidermic junction.
The dermis is constituted by a connective tissue layer of mesenchymal origin.
Finally, the inner layer is represented by the hypodermis, mainly constituted
by connective tissue. The different layers of the skin are crossed by nerve
endings and vessels. Additionally, hair follicles and glands, nonuniformly
distributed throughout the skin, are present.
