Laser Technician (International Board of Electrologist Certification) IBEC Board Exam

In which layer of the skin are mast cells primarily found?

1. Epidermis

2. Dermis (not fibrous portion)

3. Subcutaneous layer

4. Stratum corneum

The correct answer is: Dermis (not fibrous portion)

Mast cells are primarily found in the dermis, specifically within the loose connective tissue of this layer. These specialized cells play a crucial role in the immune response and inflammation. They contain granules rich in histamine and other mediators, which are released during allergic reactions and response to injury. The dermis provides a supportive framework for the skin and houses key structures such as blood vessels, nerve endings, and various immune cells, including mast cells. The presence of mast cells in the dermis is vital for monitoring the external environment and initiating an immune response when necessary. In contrast, the epidermis, which is the outermost layer of skin, does not contain mast cells; it primarily consists of keratinocytes, melanocytes, and Langerhans cells. The subcutaneous layer, while important for insulation and housing larger blood vessels and nerves, also does not house mast cells in the same way as the dermis does. The stratum corneum, being the outermost portion of the epidermis, is composed of dead keratinized cells and lacks any living cells, including mast cells.