Figure 1.

A simplified illustration of the general anatomy of the skin with the focus on autonomic nerve fibers and their innervated organs. Sweat glands, blood vessels and the arrector pili muscle are innervated by sympathetic C-fibers in the dermis. Afferent intraepidermal nerve fibers of the class C and Aδ are found in the epidermis as free nerve endings. Axon collaterals of these afferent fibers also supply blood vessels with efferent antidromic control. Small sensory fibers branch off from thicker dermal nerve bundles to create thinner subepidermal nerve bundles that innervate the epidermis.