Which layer connects the dermis to the epidermis?

The papillary layer of the dermis plays a crucial role in connecting the dermis to the epidermis. It is composed of a loose network of collagen and elastin fibers, which provides nourishment and support to the epidermis. This layer contains dermal papillae, small finger-like projections that interdigitate with the epidermis, enhancing the surface area for exchange of oxygen, nutrients, and waste products between the two layers.

The papillary layer also contains blood vessels and nerve endings, which help in providing sensation and thermoregulation to the skin. This vascular supply is vital for the health of the epidermis because it doesn't have its own blood supply; instead, it receives nutrients through diffusion from the dermis.

In contrast, the other layers mentioned are either part of the epidermis or are located deeper than the dermis. The stratum granulosum and stratum corneum are both layers of the epidermis, primarily involved in keratinization and forming a protective barrier, while the subcutaneous layer is a deeper layer of fat and tissue located beneath the dermis, helping to insulate the body and absorb shock, but not directly connecting the dermis to the epidermis.