Hypodermis

The hypodermis or subcutaneous layer, lies below the dermis. Though it is not part of the integumentary system, it is essential, as it connects the skin with the underlying skeletal muscles and bones.

Similar to the reticular dermis, the hypodermis also contains the pressure-sensing receptors called Pacinian corpuscles.

Arteries which nourish the skin are present in the hypodermis. Branches of these arteries form two networks — the cutaneous plexus present along the border of the hypodermis and the reticular layer; and the papillary plexus, a collection of smaller arteries that run into the papillary dermis.

The hypodermis primarily consists of adipocytes containing fat, which act as an energy reserve and an insulator to reduce heat loss. This subcutaneous fat accounts for approximately 80% of body fat which varies with gender and age.