The hypodermis, also known as the subcutaneous layer, is the deepest layer of the skin. It is primarily composed of loose connective tissue and fat cells, which help insulate the body and store energy. This layer acts as a cushion, protecting underlying muscles and bones from external trauma. In addition to its protective functions, the hypodermis plays a role in thermoregulation and the absorption of certain medications. It contains larger blood vessels and nerves that connect to the upper layers of the skin, including the epidermis and dermis. Overall, the hypodermis is essential for maintaining skin health and body temperature.