[Histophysiology of the epidermis]

This literature review summarizes the data on the general principles of the structure and functions of keratinocytes, melanocytes, dendritic cells (DC) and tactile epithelial cells. Special attention is paid to the process of keratinization, the formation of lipid barrier of the stratum corneum. The problem of the stem and transitional cell surface markers is discussed. Detailed current data are presented on the structure and functions of keratinosomes, their participation in the process of desquamation and the formation of intercellular cement, forming the basis of polar lipids. It is shown that lipid profile of the intercellular space of the stratum corneum is changing in the direction of the surface of the epidermis. Considerable part of the review is devoted to the data demonstrating the functions of keratinocytes: synthesis of mitogens, chemokines that attract DC and T-lymphocytes to the epidermis; production of antimicrobial peptides. In this report, the questions are discussed of the existence of two types of tactile epitheliocytes, of the participation of DC in the process of keratinization, on the transfer of information on an antigen to T-lymphocytes. The data are presented on the participation of melanocytes in the protective function of the epidermis.