Wisconsin Esthetics State Board Practice Test

Which of the following cells helps identify foreign substances in the skin?

1. Merkel cells

2. T cells

3. Langerhans cells

4. Keratinocytes

The correct answer is: Langerhans cells

Langerhans cells play a crucial role in the immune response of the skin by helping to identify foreign substances. These specialized dendritic cells are part of the skin's immune system and are primarily located in the epidermis. Their primary function is to capture, process, and present antigens (foreign substances such as bacteria and viruses) to T cells, which are vital for initiating an immune response. When Langerhans cells detect these foreign invaders, they migrate to the lymph nodes and activate the immune system, thereby helping to protect the body from infections and diseases. In contrast, other types of cells mentioned do not have this specific role. Merkel cells are involved in the sensation of touch, T cells are primarily responsible for orchestrating the overall immune response once activated but do not directly identify pathogens in the skin, and keratinocytes are the predominant cell type in the epidermis that primarily function in forming a protective barrier and producing keratin. Hence, Langerhans cells are critical in recognizing threats to the skin and assisting in the immune surveillance process.