Undirhúðin

Undirhúðin, also known as the hypodermis or subcutaneous tissue, is the deepest layer of the skin. It lies beneath the dermis and is primarily composed of loose connective tissue and adipose tissue (fat). The main function of the hypodermis is insulation, helping to regulate body temperature by retaining heat. It also serves as an energy reserve, storing fat that the body can metabolize when needed.

This layer acts as a shock absorber, protecting the underlying muscles and bones from physical trauma. The hypodermis is also where many blood vessels and nerves pass through to supply the epidermis and dermis. It connects the skin to the underlying fascia, which is the connective tissue that surrounds muscles and organs. The thickness of the hypodermis varies considerably across the body and between individuals, depending on factors such as genetics, diet, and physical activity. In some areas, like the abdomen and buttocks, the hypodermis can be quite thick, while in others, such as the eyelids, it is very thin. While not technically considered a part of the skin by some definitions, it is intimately associated with it and plays a crucial role in overall skin function and body physiology.