What does the Stratum Corneum primarily consist of?

The Stratum Corneum, which is the outermost layer of the epidermis, primarily consists of dead, flattened keratinocytes. This layer plays a crucial role in the skin's barrier function, protecting underlying tissues from environmental damage, pathogens, and moisture loss. These keratinocytes are filled with keratin, a fibrous protein that provides strength and resilience. As they move to the surface of the skin, they undergo a process of keratinization, which leads to their flattening and eventual death, forming the thick protective layer characteristic of the Stratum Corneum.

Living cells, such as those found in the deeper layers of the epidermis (like the Stratum Basale), contribute to regeneration and growth but are not present in the Stratum Corneum itself. While collagen fibers are a crucial component of the dermis, they are not a part of the epidermal layers where the Stratum Corneum is located. Pigment cells, or melanocytes, primarily reside in deeper layers of the epidermis and are responsible for skin pigmentation rather than contributing to the structure of the Stratum Corneum. Thus, the predominant material of the Stratum Corneum is indeed dead, flattened keratinocytes, fulfilling vital