CHAPTER 1 6Skin, Touch, and Movement
Our skin is our largest sensory organ. Dendrites of somatosensory
(Greek soma = body) neurons terminate in the top layers of skin, and
the membranes of these nerve fibers contain receptor proteins that
respond to touches, pokes, or changes of temperature (Fig. 16.1). Some
nerve fibers have free endings in the skin’s top layers. Sometimes the
endings are closely associated with hair follicles. Some nerve fibers
end in structures (Merkel’s disks, Pacinian corpuscles, Meissner’s
corpuscles, Ruffini endings) that respond to the pressure associated
with touch. (These are named after German and Italian anatomists
who first described these structures: Georg Meissner [1829-1905],
Friedrich Merkel [1845-1919], Filippo Pacini [1812-1883], and Angelo
Ruffini [1864-1929].)