Meissner corpuscles
Meissner bodies or Meissner tactile bodies - named after their discoverer, the German anatomist and physiologist Georg Meissner - are pressure receptors in the inguinal skin . They occur in both the inguinal and the field skin, in the stratum papillare of the dermis.
The elongated oval Meissner corpuscle belongs to the group of lamellar corpuscles without a perineural capsule. The corpuscle is approx. 100–150 μm long and 40–70 μm wide and is supplied by 1–7 dendritic axons , which are wound in a helix and between which there are stacks of Schwann cells . They are pseudounipolar neurons .
The Meissner corpuscles react to changes in pressure. They are among the rapidly adapting (RA) mechanoreceptors , so they only fire when the stimulus strength changes. They are speed sensors that signal the pressing of the skin as a change in pressure, but adapt to the new, lower position of the object being pressed in, and thus no longer emit any further signals . The adaptation to a constant pressure stimulus takes place very quickly, within 50–500 ms.
RA sensors of the monkey hand already reacted in experiments to elevations of 4 µm, which illustrates the special importance of these sensors for the human sense of touch. As when reading the Braille plays an important role. The skin's sense of touch is mediated by other mechanosensors that are specialized in certain stimuli: the Merkel cells react to pressure intensity, Ruffini corpuscles react to stretching stimuli and the Vater Pacini lamellar corpuscles react to vibration.
Meissner tactile corpuscles are located in the stratum papillare of the dermis of the inguinal skin ; they are particularly large in the fingertips. They are also found in the subepithelial connective tissue of the penis , anus and the oral mucosa . The Meissner corpuscles are missing in the hairy skin; here there are hair follicle sensors that are similarly structured.
More pictures
Representation of a Meissner corpuscle from 1918, particularly the “spotty” depicted Schwann cells and the helically winding axons
A Meissner corpuscle (tip of the black pointer) in the light microscope. The localization in the stratum papillare of the corium is clearly visible.
Hairy human skin with the representation of the Meissner corpuscle
swell
- ^ Pschyrembel clinical dictionary , 260th edition, de Gruyter, Berlin 2004
- ^ Korf, Dehghani: "Meissner Körperchen" in: electronic learning program Histo-Online , Frankfurt 2007. Accessed January 19, 2009
- ↑ a b Welsch: Textbook Histology , 2nd edition, Elsevier, Munich 2006.
- ^ Kötter: Lecture tactile sensation , Düsseldorf 2006. Retrieved January 19, 2009.
- ^ A b Schmidt, Lang, Thews: Physiologie des Menschen, 29th edition, Springer, Heidelberg 2005.
