New Jersey State Board Prometric Practice Exam

Keratin is a vital protein that plays a key role in forming the protective barrier of the skin. It is produced in the epidermis, specifically within the inner layers where keratinocytes are predominantly found. The stratum granulosum, being one of the specific layers of the epidermis, is where keratinocytes start to undergo a process called keratinization. During this process, keratinocytes move up from the stratum basale through the layers of the epidermis to the stratum corneum. In the stratum granulosum, they begin to flatten and accumulate keratin and other proteins. This layer marks the transition from living cells to the dead, flattened, and keratin-filled cells that make up the outermost layer of the skin, which is crucial for protection against environmental damage and pathogens. While the epidermis overall is responsible for keratin production, the stratum granulosum is particularly significant as it is where the keratinization process becomes evident, leading to the formation of the outer barrier of the skin.