The Nikon MicroscopyU confocal microscopy image gallery was created with a PCM-2000 confocal scanning system interfaced to a Nikon Eclipse E600 upright microscope. Images were recorded in successive z-axis serial sections with C-Imaging Systems software with excitation illumination provided by an argon-ion and/or a helium-neon laser.

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The onion-like Vater-Pacini corpuscles are mechanoreceptors found in the pancreas of cats, but not humans. In humans, the pressure-sensitive, encapsulated nerve fibers are the largest (1 to 4 millimeters in length) lamellated (layered) bodies found in skin, nipples, genitalia, ligaments, and tendons. Together, with the non-encapsulated receptors and the Meissner corpuscle (tactile and touch receptor), Ruffini corpuscle (heat receptor), and Krause corpuscle (cold receptor), they compose the mechanoreceptor system that provides stimuli to the somatosensory cortex of the brain. These corpuscles are responsible for detecting pressure or coarse touch, vibration and tension.

The core of the Vater-Pacini corpuscle contains a single, unbranched, non-myelinated nerve fiber, which has several club-like terminals. The innervating neuron becomes myelinated once it leaves the Pacinian corpuscle on its way to the cerebral cortex. The concentric lamellae are flattened neurolemmocytes (the source of the myelin sheaths) and are separated by interstitial fluid space and delicate collagen fibers. Pressure is translated as a mechanical stimulus through the connective tissue layers and fluid, exciting the core receptor axon.

Discovered by Vater and described by his student, Cardinal Karl Lehmann in 1741, it was about 100 years later that Fillipo Pacini, an Italian anatomist devoted to microscopic research, took up their study and function as well as their distribution in the human body. Pacinian corpuscles are located in the deep layers of the dermis of both hairy and glabrous (smooth) skin (e.g., fingers and toes) and in the mesentary tissue of some organs.