American Academy of Professional Coders (AAPC) Practice Exam

What is the composition of the epidermis?

1. 3 to 4 layers

2. 4 to 5 layers

3. 5 to 6 layers

4. 2 to 3 layers

The correct answer is: 4 to 5 layers

The epidermis, which is the outermost layer of the skin, is typically composed of 4 to 5 layers of cells, depending on the location of the skin on the body. In most areas, the epidermis has four primary layers: the stratum corneum, stratum granulosum, stratum spinosum, and stratum basale. In thicker skin, such as the palms of the hands and soles of the feet, an additional layer known as the stratum lucidum is often present, which accounts for the total of five layers. Each of these layers has a specific function related to the overall health and protection of the skin, including barrier formation, moisture retention, and cell production. The distinction in the number of layers is significant in understanding skin health and various dermatological conditions. Thus, recognizing that the epidermis typically encompasses 4 to 5 layers is foundational in dermatology and contributes to a comprehensive understanding of skin anatomy.