Esthetics Core Written Practice Test

Keratinocytes are the predominant cells found in the epidermis, the outermost layer of the skin. Their primary role is to form a protective barrier. This barrier is essential for preventing water loss and protecting the underlying tissues from environmental damage, pathogens, and harmful substances.

Keratinocytes achieve this by undergoing a process known as keratinization, where they produce keratin, a tough, fibrous protein. As these cells move from the basal layer of the epidermis to the surface, they gradually fill with keratin and ultimately die, creating a robust layer that protects the skin.

In contrast, the roles of regeneration of nerves, production of moisture, and transmission of signals are not primarily associated with keratinocytes. Nerve regeneration is generally related to specialized nerve cells, moisture production is mainly managed by sebaceous and sweat glands, and signal transmission is typically carried out by neurons and their connections. Thus, the formation of the protective barrier is the definitive and critical role of keratinocytes in the skin.