Chapter 2. Prehension

Meissner
corpuscle
Chapter 6 - During Contact 223
Figure 6.6 The four morphologically distinct types of
mechanoreceptors in glabrous skin. Two are rapidly adapting (FA)
receptors: the Meissner corpuscles, located in dermal papillae; and
the Pacinian corpuscles, located in subcutaneous tissue below the
dermis (in glabrous and hairy skin). There are also two slow
adapting (SA) receptors: Merkel receptors, located in dermal
papillae; and Ruffini corpuscles, located deeper in the demris.
(from Kandel & Schwartz, 1985; reprinted by permission).
nerve terminal. Removal of these rings transforms the receptor from a
fast to a slow adapting one. Ruffini ending or corpuscles are located
in the deeper, reticular layers of the dermis, usually above Pacinian
corpuscles.
These cutaneous mechanoreceptors give rise to myelinated,
afferent fibers with similar diameters and fast conduction velocities of
35-80 m/s (Johansson and Vallbo, 1983). The mechanoreceptive
afferent units have been studied extensively (Johansson, 1978;
Johansson & Vallbo, 1980, 1983) and differ mainly with respect to:
morphology and location of receptors; organization of afferent
terminals in the spinal cord; receptive field size (the area of skin within