Which layer of the epidermis is responsible for forming keratin?

The stratum granulosum is the layer of the epidermis primarily responsible for forming keratin. This layer is situated above the stratum spinosum and below the stratum corneum. In the stratum granulosum, keratinocytes undergo a process called keratinization, where they begin to produce keratin, a fibrous protein that provides strength and resilience to the skin.

As these cells migrate upward through the epidermis, they are gradually filled with keratin, leading to their eventual death and the formation of a tough protective layer in the outermost stratum corneum. This contributes to the skin's barrier function, preventing water loss and protecting against environmental damage.

In contrast, the other layers serve different functions. The stratum corneum consists of dead, flattened keratinized cells that form a protective outer barrier but does not actively produce keratin. The stratum lucidum, found only in thick skin areas, provides an additional barrier but is not directly involved in keratin production. The stratum basale contains melanocytes and is the site of new cell generation, but it is not where keratin is primarily formed. This essential understanding of the epidermal layers highlights the unique role of the stratum