American Academy of Professional Coders (AAPC) Practice Exam

Which of the following layers of the epidermis is closest to the underlying dermis?

1. Stratum Corneum

2. Stratum Lucidum

3. Stratum Basale

4. Stratum Granulosum

The correct answer is: Stratum Basale

The layer of the epidermis that is closest to the underlying dermis is the Stratum Basale. This layer, also known as the stratum germinativum, is vital for skin regeneration as it contains the basal cells responsible for producing new keratinocytes. These cells continuously divide and move upward through the layers of the epidermis, ultimately making their way to the outermost layer. Being in direct contact with the dermis allows the Stratum Basale to receive nutrients and other support from the dermal tissue beneath it, facilitating the ongoing process of cellular turnover and repair. As the basal cells proliferate, they also play a significant role in the overall maintenance and health of the skin, as they are the source for the cells found in the higher epidermal layers. In this context, while the other layers have their distinct functions and characteristics, none are as directly connected to the dermis as the Stratum Basale, making it the correct choice.