Some of the main functions of skin cells are to provide protection, perceive and transmit sensation, control evaporation and regulate temperature. Skin cells, which are epithelial cells, are also self-repairing and reproduce quickly. Epithelial cells are the most commonly found of the four tissue types.
Skin cells represent the first line of defense against pathogens found in the external environment. Known collectively as the intergumentary system, skin cells create a semi-impermeable barrier that also reduces bodily fluid loss. The endings of neurons are found in skin cells and enable the transmission of external stimuli to the central nervous system. There are two basic types of skin cells: epidermal cells, which comprise the outermost layer of skin, and dermal cells, which form the underlying connective tissue.
The most predominant type of epidermal skin cells are the keratinocytes. Langerhans cells, Merkel cells and melanocytes are also found in the epidermis. The keratinocytes, however, provide the epidermis with its primary functional qualities of toughness, impermeability and healing from injuries through self-replacement. Blood vessels are not found in the epidermis. The skin cells there receive nourishment from capillaries in the upper portion of the underlying dermis through a process of diffusion. The epidermis is tightly connected to the dermis through a thin sheet of fibers called the basement membrane, which also controls the transfer of molecules and cells between the two layers of skin.