<P> The epidermis contains no blood vessels , and cells in the deepest layers are nourished almost exclusively by diffused oxygen from the surrounding air and to a far lesser degree by blood capillaries extending to the outer layers of the dermis . The main type of cells which make up the epidermis are Merkel cells , keratinocytes , with melanocytes and Langerhans cells also present . The epidermis can be further subdivided into the following strata ( beginning with the outermost layer ) : corneum , lucidum ( only in palms of hands and bottoms of feet ) , granulosum , spinosum , basale . Cells are formed through mitosis at the basale layer . The daughter cells ( see cell division ) move up the strata changing shape and composition as they die due to isolation from their blood source . The cytoplasm is released and the protein keratin is inserted . They eventually reach the corneum and slough off ( desquamation ) . This process is called `` keratinization '' . This keratinized layer of skin is responsible for keeping water in the body and keeping other harmful chemicals and pathogens out , making skin a natural barrier to infection . </P>
the outer layer of the skin that contains no blood or nerve supply is the
epidermis