Which layer of the skin is primarily composed of fat and connective tissue?

The subcutaneous layer, also known as the hypodermis, is primarily composed of fat and connective tissue. This layer is situated beneath the dermis and plays crucial roles in the body. One of its main functions is to insulate the body, helping to maintain temperature by serving as a barrier against heat loss. Additionally, the fat stored in this layer acts as an energy reserve and provides cushioning to protect underlying structures, such as muscles and bones, from trauma.

In contrast, the epidermis is the outermost layer of skin, comprising stratified epithelium that provides a protective barrier. The dermis lies beneath the epidermis and contains important structures such as blood vessels, hair follicles, and sweat glands, mainly made up of connective tissue, but it does not have the fat composition that characterizes the hypodermis. The stratum corneum is the outermost part of the epidermis, consisting of dead skin cells that have undergone keratinization, and it is also unrelated to fat storage. Understanding these differences highlights why the hypodermis is specifically associated with fat and connective tissue.