What describes the stratum granulosum?

The stratum granulosum is a key layer of the epidermis that is characterized by the presence of keratinocytes that contain small, keratohyalin granules. These granules are important for the process of keratinization, where the cells begin to die and fill with keratin, making the skin more resilient and water-resistant. This layer serves as a transitional zone between the deeper layers, where cells are still alive and metabolically active, and the outer layers, which are primarily composed of dead keratinized cells that provide a barrier to the environment.

The granules in this layer play a significant role in the production of lipids, which help to form the skin's barrier and prevent water loss. Thus, the presence of these small granules is a definitive characteristic of the stratum granulosum, underscoring its importance in skin health and function.