The skin is the outer covering of the body and is vital in protecting the body against pathogens and excessive water loss. Its other important functions include insulation, temperature regulation and sensation. The skin of humans and other mammals is composed of two major layers: (1) epidermis (the more superficial layer) and (2) dermis (the deeper layer). The dermis can be further divided into two major layers: the papillary dermis and the reticular dermis.
One of the primary distinctions of the reticular dermis from the papillary dermis is location. The papillary dermis is located above the reticular dermis and therefore lies next to the epidermal layer of the skin. The basement membrane separates the papillary layer from the epidermis. The reticular dermis is the deeper layer, situated next to the papillary layer. It is also the thicker layer compared with the papillary layer. The reticular dermis is composed of dense irregular connective tissue. The presence of these connective tissues makes the dermis elastic. Other components of the reticular dermis include sweat glands, sebaceous glands, receptors, and blood vessels. In human skin, the reticular dermis also includes the hair roots and nails.