What is the primary purpose of the stratum granulosum?

The primary purpose of the stratum granulosum is indeed to help in the process of cell death. This layer is located above the stratum spinosum in the epidermis and plays a significant role in the transition of living keratinocytes into dead cells, which eventually form the outermost protective barrier of the skin.

In this layer, keratinocytes undergo a process called keratinization, where they begin to flatten, lose their nuclei, and accumulate keratohyalin granules. These granules contain proteins that help in the formation of keratin, a key structural component of the skin, providing durability and protection as the cells move upwards to the surface.

Furthermore, the stratum granulosum also contributes to the formation of the lipid barrier that helps prevent water loss from the skin, which is essential in maintaining hydration and overall skin health. Thus, its primary role is intricately connected with the ongoing process of cell death and the formation of the skin's barrier function, rather than any of the other options presented, which do not directly reflect the specific functions of this layer.