Pennsylvania Esthetician State Board Practice Exam

What is the main protective layer of the skin called?

1. Epidermis

2. Dermis

3. Hypodermis

4. Stratum Lucidum

The correct answer is: Epidermis

The epidermis is indeed the main protective layer of the skin. It serves as the outermost barrier that protects the underlying tissues from environmental factors such as pathogens, chemicals, and physical abrasions. Comprised primarily of keratinocytes, the epidermis is responsible for the formation of a tough, protective layer that helps to prevent water loss and maintains hydration in the skin. This layer also plays a crucial role in the skin's coloration through the presence of melanocytes, which produce melanin, the pigment responsible for skin tone. The epidermis is continuously renewing itself, as older cells at the surface slough off and new cells are generated from beneath. The other layers mentioned in the choices have different functions. The dermis, located beneath the epidermis, supports and nourishes the skin with blood vessels, hair follicles, and glands. The hypodermis, or subcutaneous layer, primarily serves as a fat storage site and insulates the body. The stratum lucidum is a specific sub-layer within the epidermis, found in thicker skin areas, but it does not represent the whole protective layer of the skin. Thus, identifying the epidermis as the main protective outer layer is accurate.