Massachusetts State Board Esthetics Practice Exam

What type of cells are keratinocytes?

1. Cells that produce melanin

2. Cells responsible for hair growth

3. Cells that produce keratin

4. Cells that support immune functions

The correct answer is: Cells that produce keratin

Keratinocytes are primarily known for their role in producing keratin, which is a key structural protein found in the skin, hair, and nails. This protein is crucial for the protective barrier function of the skin, helping to prevent water loss and protect against environmental damage. Throughout their lifecycle, keratinocytes undergo a process called keratinization, where they move from the basal layer of the epidermis to the surface, undergoing changes that culminate in the formation of a tough, protective layer of dead cells, primarily composed of keratin. The other choices each refer to different types of cells with distinct functions. Cells that produce melanin are known as melanocytes, which are responsible for pigmentation in the skin. The cells responsible for hair growth are hair follicle epithelial cells and other specific cells like dermal papilla cells. Lastly, cells that support immune functions within the skin are primarily Langerhans cells, a type of dendritic cell involved in the immune response. Thus, keratinocytes' defining role as the producers of keratin solidifies the correctness of the chosen answer.