| Human skin comprises two types. | Thick skin, limited to the palms and soles, lacks hair and has abundant sweat glands. |
| Thin skin has hairs and covers the rest of the body. |
Thick or thin, the skin consists of two distinct but tightly attached layers—the epidermis and dermis—which are underlain by the hypodermis.
02. Dermal–epidermal junction.
Hypodermis. Although not a part of the skin, this layer of mesoderm-derived loose connective and adipose tissue under the dermis flexibly binds the skin to deeper structures. Its thickness varies, depending on nutritional status, activity level, body region, and gender. It is also called subcutaneous fascia and, where it is thick enough, the panniculus adiposus.
Glands (sebaceous and sweat), hairs, and nails arise from epidermal downgrowths into the dermis during embryonic development. These structures, which are mainly of epithelial origin, require epithelial-mesenchymal interactions between the epidermis and dermis for their formation and maintenance.