Which layer of tissue attaches skin to underlying organs and is not part of the skin?

The subcutaneous layer, also known as the hypodermis, plays a crucial role in the structure of the skin and its relation to underlying organs. This layer consists primarily of loose connective tissue and adipose tissue, providing insulation and cushioning for the body. It serves as a conduit for larger blood vessels and nerves that can branch out into the dermis, which is the layer of skin beneath the epidermis.

Understanding the function of the subcutaneous layer clarifies why it is not considered part of the skin itself. In contrast, the epidermis is the outermost protective layer of skin, while the dermis contains vital structures such as hair follicles, sweat glands, and sensory receptors. Neither of these layers is responsible for the attachment of skin to underlying organs; that function is entirely the role of the subcutaneous layer. Thus, the correct identification of the hypodermis as the tissue layer that connects the skin to underlying organs underscores its significance in structural support and overall integumentary system function.