What forms the cells that resemble granules in the stratum granulosum?

• A. Collagen
• B. Keratin
• C. Elastin
• D. Melanin

Answer: (B)

The cells that resemble granules in the stratum granulosum primarily consist of keratin. In this layer of the epidermis, keratinocytes undergo a process called keratinization, where they produce keratin, a fibrous protein that is crucial for the protective barrier function of the skin. As these cells move up from the deeper layers, they begin to flatten and fill with keratin, creating a keratin-rich environment that gives the granules their distinctive appearance. The granules themselves are filled with keratohyalin, a protein that contributes to the formation of the keratin matrix, aiding in the toughening and water-proofing of the skin surface.

This process is central to the skin’s ability to protect underlying tissues and prevent water loss, reinforcing the importance of keratin in the skin’s physiology and histology. The other substances listed, such as collagen, elastin, and melanin, play vital roles in the skin as well, but they do not form the granules identified in the stratum granulosum. Collagen and elastin are primarily found in the dermis and contribute to skin elasticity and strength, while melanin provides pigmentation and protects against UV radiation, but neither of these directly contributes to the