Nerve supply to the skin the kind of sensory inputs which project to a specific region of the primary somatosensory cortex. Groups of nerve terminals located in the different layers of the skin are categorized depending on whether the skin is hairy, nonhairy, or an exposed mucous membrane. The hairy parts of the body such as the forearm or the leg have two groups of nerve endings: those that end along with the hair follicles, and also with the arborizations of unmyelinated axons which are referred to as “free” nerve endings because they are served by both myelinated and unmyelinated axons. Nonhairy skin, such as
Nerve supply to the skin the palms of hands and the soles of feet, has three types of nerve terminations. The first one, Meissner’s corpuscles are encapsulated nerve endings attached to the epidermis in the dermal papilli that detect changes in texture and vibrations. Merkel's discs are arborizations of nonmyelinated axons that end in terminals on specialized tactile cells and which detect sustained touch and pressure. Lastly, there are also “free” nerve endings which are similar in structure to those in hairy skin, though they are more numerous. The exposed mucous membranes of the lips, the anal mucous membrane, and the external genital organs form