Adult skin structure, anatomy, appendages of the integumentary system. This illustration represents a 3D section view of 3/4 of the anatomy and structure of the skin with all its appendages. The skin is made up of 3 layers, especially from top to bottom:. The epidermis is the outermost layer, made up of keratinocytes. The keratinocytes mature on the surface of the skin where the dead keratinized cells desquamate. The dermis represents the second layer between the epidermis and the hypodermis. It is made up of connective-type tissue. We usually distinguish the papillary dermis adjoining the dermo-epidermal junction, the reticular dermis and the deep dermis. There are different elements present in the dermis, eccrine sweat glands, nerve endings, blood vessels. But also the pilosebaceous apparatus crosses the epidermis and the dermis. It is made up of a hair follicle and various appendages. These annexes are the sebaceous gland (sebum), the pilomotor or arrector muscle of the hair, the apocrine sweat gland (sweat). The apocrine sweat gland is only present in certain parts of the body such as the armpits, around the anus and nipples, and the hypodermis forms the last layer, made up of fatty tissue and connective tissue located under the dermis.