Other nerve endings associate with Merkel cells in the epidermis. Meissner s corpuscles reside in the dermal papillae and function as mechanoreceptors in touch perception. The hypodermis is composed of loose connective tissue with large numbers of adipose cells . The hypodermis provides insulation, shock absorption, energy storage, and the ability of skin to slide over joints. It also contains the major blood vessels of the skin.
Many epidermal appendages extend into the hypodermis.
These provide a source of keratinocytes when the epidermis is destroyed by abrasion or burns. Hair is composed of dead epidermal cells that have undergone a modified epidermal keratinization including the expression of specific keratin proteins that are highly crosslinked by disulfide bonds. It is derived from hair folicles , which are epidermal invaginations that project into the dermis or hypodermis. The number of hairs on all primates is similar, but most is vellus on humans and terminal on other primates. Hair functions in thermoregulation in most mammals.