Additionally, these corpuscles may detect the sensation of slip between an object and the skin, allowing for grip control.
Function of free nerve endings in skin skin#
Meissner corpuscles are most sensitive to low-frequency vibrations between 10 to 50 Hertz and can respond to skin indentations of less than 10 micrometers. Meissner corpuscles consist of a cutaneous nerve ending responsible for transmitting the sensations of fine, discriminative touch and vibration. Animal studies involving knockout of BDNF or TrkB in mice resulted in a lack of Meissner corpuscles, highlighting the importance of this signaling system in corpuscular development. TrkB is an enzyme-linked transmembrane receptor encoded by the NTRK2 gene. The development of Meissner corpuscles is dependent on brain-derived neurotrophic receptor (BDNF) signaling via tropomyosin receptor kinase B (TrkB). A single neuron from the sensory ganglion is capable of supplying multiple corpuscles. The cell body of the supplying neuron resides within a dorsal root ganglion or cranial nerve sensory ganglion. The nerve fiber branches multiple times, forming bulbous expansions as it meanders tortuously throughout the lamellae. The nerve fiber retains its myelin sheath as it enters the corpuscle but becomes amyelinic after a short distance. Typically, corpuscles are supplied by a single axon, but corpuscles with 2 to 7 accessory branches from the primary axon have been documented. Innervation by additional unmyelinated C fibers has also been reported, although these fibers may simply pass through the corpuscle to reach the epidermis. In this region, collagen fibrils from the interlamellar matrix extend into the dermis and anchor the receptor to the basal aspect of the epidermis.Įach corpuscle is supplied by a nerve ending derived from an intermediate-large amyloid-beta myelinated afferent fiber. The deeper aspect of the corpuscle is lined by two to four layers of fibroblasts and fibrillary matrix. The capsule of Meissner corpuscles is derived from the endoneurial-perineural fibroblastic connective tissue. The flattened Schwann cells are organized in a stacked conformation in a background of an interlamellar matrix composed largely of collagen and microfilaments. Both the size and density of the receptors depend on the site of origin.Įach corpuscle is comprised of three primary components: elongated Schwann cells, a connective tissue capsule, and a central axon. One corpuscle may be found within every two to four dermal papillae, with less than three corpuscles per papilla.
The corpuscles are approximately 20 to 40 micrometers in diameter and 80 to 150 micrometers in length, with their long axis oriented perpendicularly to the skin surface.
Meissner corpuscles are ellipsoid mechanoreceptors located superficially within the dermal papillae at a depth of approximately 150 micrometers.
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