Pacinian corpuscle: Function, Anatomy & Role in Touch

Introduction to Pacinian Corpuscle

The Pacinian corpuscle is a specialized mechanoreceptor found in the skin and various other tissues of the body. It plays a crucial role in detecting vibrations and pressure, contributing to the sense of touch. First discovered in the 18th century, these oval-shaped structures are named after their discoverers, Abraham Vater and Filippo Pacini [1].

Anatomy and Structure

The Pacinian corpuscle has a distinctive onion-like structure, consisting of concentric layers of connective tissue. At the center lies a myelinated nerve ending, which is sensitive to mechanical stimuli. The outer layers are composed of flattened cells and collagen fibers, providing a protective capsule. These corpuscles are relatively large, measuring about 1 mm in length, and can be easily seen with the naked eye [2].

Distribution in the Body

Pacinian corpuscles are widely distributed throughout the body. They can be found in both hairy and hairless (glabrous) skin, as well as in various internal organs (viscera), joints, and attached to the periosteum of bones. High concentrations are present in the hands, feet, and mesentery [3].

Functional Mechanism

As mechanoreceptors, Pacinian corpuscles are exquisitely sensitive to vibrations and pressure. The layered structure helps reduce mechanical sensitivity, allowing the corpuscle to detect subtle changes in pressure and vibration. When stimulated, the nerve ending at the core generates an action potential, transmitting the sensory information to the central nervous system.

Physiological Role

Pacinian corpuscles are part of the somatosensory system, contributing to the perception of touch, pressure, and vibration. They work in concert with other mechanoreceptors, such as Meissner’s corpuscles, to provide a comprehensive sense of touch. Pacinian corpuscles are particularly responsive to high-frequency vibrations and deep pressure.

Clinical Relevance

Dysfunction or damage to Pacinian corpuscles can lead to altered tactile sensitivity and sensory disorders. One rare condition is Pacinian neurofibroma (Pacinian neuroma), a benign tumor that affects these corpuscles. Additionally, studying the distribution and function of Pacinian corpuscles can provide insights into various sensory disorders and guide diagnostic approaches.

Historical and Eponymous Context

The Pacinian corpuscle is named after two prominent anatomists: Abraham Vater, who first described the structure in 1741, and Filippo Pacini, who provided a more detailed description in 1835. Hence, they are also known as Vater-Pacini corpuscles or lamellar corpuscles, acknowledging the contributions of both scientists.

Microscopic and Radiologic Examination

Histological techniques, such as staining and microscopy, are used to study the detailed structure of Pacinian corpuscles. They can be visualized using various microscopic methods, including light microscopy and electron microscopy. Radiological imaging, such as ultrasound or MRI, can also help identify and locate these corpuscles in living tissues.

Research and Novel Findings

Ongoing research continues to unravel the complexities of Pacinian corpuscles and their role in somatosensation. Recent studies have provided new insights into their distribution, molecular mechanisms, and potential therapeutic targets. For example, a study by Shenton et al. (2020) revealed the presence of Pacinian corpuscles in unexpected locations, such as the pancreas [4].

Comparison with Other Mechanoreceptors

Pacinian corpuscles are one of several types of mechanoreceptors found in the skin and other tissues. They differ from other receptors, such as Meissner’s corpuscles and Merkel cells, in terms of their structure, location, and specific sensitivity to mechanical stimuli. However, all these mechanoreceptors work together to provide a comprehensive picture of tactile sensations.

In conclusion, the Pacinian corpuscle is a fascinating and essential component of the somatosensory system. Its unique structure and sensitivity to vibrations and pressure make it a key player in the perception of touch. Ongoing research continues to shed light on the intricacies of these corpuscles and their role in sensory physiology and pathology.