PSI Barbering Practice Exam

Which layer of the epidermis is responsible for the growth of the epidermis?

1. Stratum corneum

2. Stratum lucidum

3. Stratum granulosum

4. Stratum germinativum

The correct answer is: Stratum germinativum

The layer of the epidermis responsible for the growth of the epidermis is the stratum germinativum. This is the deepest layer of the epidermis, also known as the basal layer. Within this layer, keratinocytes are produced through mitosis, which continuously generates new cells that move upward through the epidermis to replace those that are shed on the skin's surface. The stratum germinativum also contains melanocytes, which produce melanin, contributing to the skin's pigmentation. The other layers mentioned in the options serve different functions. The stratum corneum is the outermost layer, primarily composed of dead keratinized cells that protect underlying layers. The stratum lucidum, found only in specific areas of thick skin, provides an additional layer of protection but does not contribute to cell growth. The stratum granulosum contains keratinocytes that start to lose their nuclei and begin the process of keratinization, playing a significant role in the barrier function but not in the growth of the epidermis itself.