Which skin layer is primarily responsible for thermoregulation?

The primary skin layer responsible for thermoregulation is the reticular dermis. This layer contains a rich supply of blood vessels and sweat glands, both of which play critical roles in temperature regulation. When body temperature rises, blood vessels in the reticular dermis dilate, allowing more blood to flow near the surface of the skin, which facilitates heat loss through radiation. Additionally, the sweat glands in this layer produce sweat, which cools the body through evaporation.

The stratum corneum, located in the epidermis, serves primarily as a barrier to protect underlying tissues rather than contributing to thermoregulation. The hypodermis, while it provides insulation and helps with the temperature regulation indirectly, is not the primary layer responsible for active thermoregulatory processes. Lastly, the basal epidermis is primarily involved in the generation of new skin cells and does not play a significant role in thermoregulation. The important functions of the reticular dermis in maintaining body temperature underscore its critical role in thermoregulation.