Pacinian corpuscle

Pacinian corpuscles (or Lamellar corpuscles) are one of the four major types of mechanoreceptor. They are nerve endings in the skin responsible for sensitivity to vibration and pressure. Vibrational role specifically helps detect surface texture, e.g., rough vs. smooth. Pacinian corpuscles are the most obvious as they form large structures (up to 1 mm long), easiest to see in routine histology.

Structure

Pacinian corpuscles are oval-shaped and approximately 1 mm in length. The corpuscle is layered like an onion; each layer is a thin, flat Schwann cell. Inside the corpuscle, there is a non-myelinated terminal axon.

Function

Pacinian corpuscles detect gross pressure changes and vibrations. Any deformation in the corpuscle causes action potentials to be generated, by deforming the neuronal membrane and causing sodium ion channels to open up.

Clinical significance

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. It is thought that they respond to high velocity changes in joint position.

See also

• Meissner's corpuscle
• Merkel cell
• Ruffini ending

References

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  Pacinian corpuscle diagram from Gray's Anatomy
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  Diagram of human skin showing various structures
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  Cross-section of skin with Pacinian corpuscle
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  Vater-Pacini corpuscle illustration
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  Microscopic image of a Pacinian corpuscle
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  Histological image of a Pacinian corpuscle