Which of the following is NOT a major cell type found in the epidermis of the skin?

• A. Keratinocyte
• B. Melanocyte
• C. Langerhans cell
• D. Fibroblast

Answer: (D)

Verified step by step guidance

1. Step 1: Begin by understanding the structure of the epidermis, which is the outermost layer of the skin. The epidermis is primarily composed of specific cell types that contribute to its function, such as protection, pigmentation, and immune defense.
2. Step 2: Identify the major cell types found in the epidermis. These include: (1) Keratinocytes, which produce keratin and form the majority of the epidermis; (2) Melanocytes, which produce melanin and contribute to skin pigmentation; and (3) Langerhans cells, which are immune cells involved in detecting pathogens.
3. Step 3: Recognize that fibroblasts are not part of the epidermis. Fibroblasts are connective tissue cells found in the dermis (the layer beneath the epidermis) and are responsible for producing collagen and extracellular matrix components.
4. Step 4: Compare the listed cell types to determine which one does not belong to the epidermis. Keratinocytes, melanocytes, and Langerhans cells are all integral to the epidermis, while fibroblasts are located in the dermis.
5. Step 5: Conclude that fibroblasts are not a major cell type found in the epidermis, as they are part of the dermis and serve a different function related to connective tissue.