|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.
|Pacinian capsule labeled at bottom.|
|Gray's||subject #233 1060|
Pacinian corpuscles are one of the four major types of mechanoreceptor, responsible for sensitivity to deep pressure touch and high frequency vibration.
Like Ruffini endings, they are found in deep subcutaneous tissue, and are considered rapidly adapting receptors, which means they will not fire action potentials throughout the duration of a stimulus but, rather, will fire briefly at its beginning and end (Kandel et al., 2000).
The Pacinian corpuscle is ovoid 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.
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 (Kandel et al., 2000). 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 (Kandel et al., 2000). 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 (Kandel et al., 2000). They only sense stimuli that occur within this field.
The term "Golgi-Mazzoni corpuscle" (distinct from the Golgi organ) is used to describe a similar structure found only in the fingertips. (c_56/12261088 at Dorland's Medical Dictionary, synd/2423 at Who Named It)
- Vater Pacini Körperchen.png
- Kandel ER, Schwartz JH, Jessell TM. Principles of Neural Science, 4th ed., p.433. McGraw-Hill, New York (2000). ISBN 0-8385-7701-6
- Virginia Commonwealth University
- Anatomy Atlases - Microscopic Anatomy, plate 06.124
- lamellated+corpuscles at eMedicine Dictionary