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Pacinian corpuscles

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Pacinian corpuscle
Pacinian corpuscle, with its system of capsules and central cavity.
a. Arterial twig, ending in capillaries, which form loops in some of the intercapsular spaces, and one penetrates to the central capsule.
b. The fibrous tissue of the stalk.
n. Nerve tube advancing to the central capsule, there losing its white matter, and stretching along the axis to the opposite end, where it ends by a tuberculated enlargement.
Latin corpusculum lamellosum
Gray's subject #233 1060
System
MeSH A08.800.550.700.500.700
Skin
Pacinian capsule labeled at bottom.

Pacinian corpuscles are one of the four major types of mechanoreceptor. They are nerve endings in the skin, responsible for sensitivity to deep pressure touch and high frequency vibration.


Structure

Similar in physiology to the Meissner's corpuscle, Pacinian corpuscles are larger and fewer in number than both Merkel cells and Meissner's corpuscles[1] .

The Pacinian corpuscle is oval shaped and approximately 1 mm in length. The entire corpuscle is wrapped by a layer of connective tissue. It has 20 to 60 concentric lamellae composed of fibrous connective tissue and fibroblasts, separated by gelatinous material. The lamellae are very thin, flat, modified Schwann cells. In the center of the corpuscle is the inner bulb, a fluid-filled cavity with a single afferent unmyelinated nerve ending.

Function

Pacinian corpuscles detect gross pressure changes and vibrations. Any deformation in the corpuscle causes action potentials to be generated, by opening pressure-sensitive sodium ion channels in the axon membrane. This allows sodium ions to influx in, creating a receptor potential.

These corpuscles are especially susceptible to vibrations, which they can sense even centimeters away [1] . Pacinian corpuscles cause action potentials when the skin is rapidly indented but not when the pressure is steady, due to the layers of connective tissue that cover the nerve ending [1] . It is thought that they respond to high velocity changes in joint position.

Pacinian corpuscles have a large receptive field on the skin's surface with an especially sensitive center [1] . They only sense stimuli that occur within this field.

Nomenclature

The Pacinian corpuscle was named after its discoverer, Italian anatomist Filippo Pacini.

The term "Golgi-Mazzoni corpuscle" (distinct from the Golgi organ) is used to describe a similar structure found only in the fingertips. [2]

Additional images

References

  1. 1.0 1.1 1.2 1.3 Kandel, Edited by Eric R.; Schwartz, James H.; Jessell, Thomas M. (2000), Principles of neural science, New York: McGraw-Hill, Health Professions Division, ISBN 0-8385-7701-6 
  2. (Who Named It synd/2423)

See also

External links



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