Merkel cell

Neuron: Merkel cell
Diagram of human skin. In humans, Merkel cells (yellow dot) are found clustered beneath the epidermal ridges (aka fingerprints).
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Merkel cells or Merkel-Ranvier cells are oval receptor cells found in the skin of vertebrates that have synaptic contacts with somatosensory afferents. They are associated with the sense of light touch discrimination of shapes and textures. They can turn malignant and form the skin tumor known as Merkel cell carcinoma.

There is evidence that they are derived from neural crest.^[1] More recent experiments in mammals have indicated that they are in fact epithelial in origin.^[2]

Location

Merkel cells are found in the skin and some parts of the mucosa (stratum germinativum) or also known as stratum basale of all vertebrates. In mammalian skin, they are clear cells found in the stratum basale (at the bottom of sweat duct ridges) of the epidermis approximately 10 µm in diameter. They also occur in epidermal invaginations of the plantar foot surface called rete ridges.^[3] Most often, they are associated with sensory nerve endings, when they are known as Merkel nerve endings (also called a Merkel cell-neurite complex). They are associated with slowly adapting (SA1) somatosensory nerve fibers.

Function

Friedrich S. Merkel referred to these cells as Tastzellen or "touch cells" but this proposed function has been controversial as it has been hard to prove. However, genetic knockout mice have recently shown that Merkel cells are essential for the specialized coding by which afferent nerves resolve fine spatial details.^[4] Merkel cells are sometimes considered APUD cells because they contain dense core granules, and thus may also have a neuroendocrine function.

Developmental origin

The origin of Merkel cells has been debated for over 20 years. Evidence from skin graft experiments in birds implies that they are neural crest derived, but experiments in mammals now demonstrate an epidermal origin.^[5][6]

See also

• Merkel nerve ending
• Merkel cell cancer

References

1. ^ K. I. Baumann; Zdenek Halata; I. Moll (2003). The Merkel cell: structure-development-function- cancerogenesis. Springer. pp. 99–. ISBN 9783540003748. http://books.google.com/books?id=Cotbt-4_8jwC&pg=PA99. Retrieved 2 May 2010. 
2. ^ Morrison, Kristin; George R. Miesegaes, Ellen A. Lumpkin, Stephen M. Maricich. (2009). "Mammalian Merkel cells are descended from the epidermal lineage.". Developmental Biology 336. doi:10.1016/j.ydbio.2009.09.032. 
3. ^ Halata, Z; Grim, M; Bauman, KI (2003). "Friedrich Sigmund Merkel and his "Merkel cell", morphology, development, and physiology: review and new results". The Anatomical Record Part A: Discoveries in Molecular, Cellular, and Evolutionary Biology 1) (271): 225–39. doi:10.1002/ar.a.10029. PMID 12552639. http://www3.interscience.wiley.com/cgi-bin/fulltext/102527525/PDFSTART. 
4. ^ Maricich SM, Wellnitz SA, Nelson AM, Lesniak DR, Gerling GJ, Lumpkin EA, Zoghbi HY. (2009). "Merkel Cells are Essential for Light Touch Responses". Science 324 (5934): 1580–82. doi:10.1126/science.1172890. PMC 2743005. PMID 19541997. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2743005. 
5. ^ Morrison KM, Miesegaes GR, Lumpkin EA, Maricich SM. (September 25, 2009). "Mammalian Merkel cells are descended from the epidermal lineage". Dev Biol 336 (1): 76–83. doi:10.1016/j.ydbio.2009.09.032. PMC 2783667. PMID 19782676. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2783667. 
6. ^ Van Keymeulen A, Mascre G, Youseff KK, Harel I, Michaux C, De Geest N, Szpalski C, Achouri Y, Bloch W, Hassan BA, Blanpain C. (2009). "Epidermal progenitors give rise to Merkel cells during embryonic development and adult homeostasis". J Cell Biol 1 (187): 91–100. doi:10.1083/jcb.200907080. PMC 2762088. PMID 19786578. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2762088. 

External links

• MeSH A08.800.550.700.500.425
• NIF Search - Merckel Disc Cell via the Neuroscience Information Framework

This anatomy article is a stub. You can help Wikipedia by expanding it.v · Categories: Nervous tissue cells Skin anatomy Anatomy stubs Wikimedia Foundation. 2010. Игры ⚽ Поможем написать реферат Jack Iverson Chisht Look at other dictionaries: Merkel cell polyomavirus — Virus classification Group: Group I (dsDNA) Family: Polyomaviridae Genus: Polyomavirus …   Wikipedia Merkel cell carcinoma — Classification and external resources Micrograph of a Merkel cell carcinoma. H E stain. ICD 10 C …   Wikipedia Merkel cell cancer — Merkel cell cancer, also called Merkel cell carcinoma, trabecular cancer, Apudoma of skin, or Small cell neuroepithelial tumor of the skin, is a rare and highly aggressive cancer where malignant cancer cells develop on or just beneath the skin… …   Wikipedia Merkel cell carcinoma — An infrequent but highly malignant type of skin cancer. Characteristically starts in a sun exposed area (of the head, neck, arms or legs) in whites 60 80 years of age as a firm, painless, shiny lump that can be red, pink, or blue in color and… …   Medical dictionary Merkel cell cancer — A rare type of cancer that forms on or just beneath the skin. Merkel cell cancer is divided into three types called trabecular, intermediate, and small cell …   English dictionary of cancer terms Merkel cell — Mer·kel cell also Merkel s cell mər kəl(z) n a cell that occurs in the basal part of the epidermis, is characterized by dense granules in its cytoplasm, is closely associated with the unmyelinated tip of a nerve fiber, and prob. functions in… …   Medical dictionary Merkel cell (corpuscle disk tactile cell) — Mer·kel cell (corpuscle, disk, tactile cell) (murґkəl) [Friedrich Sigmund Merkel, German anatomist, 1845–1919] see under cell …   Medical dictionary Carcinoma, Merkel cell — An infrequent but highly malignant type of skin cancer. Characteristically starts in a sun exposed area (of the head, neck, arms or legs) in whites 60 80 years of age as a firm, painless, shiny lump that can be red, pink, or blue in color and… …   Medical dictionary stage I Merkel cell carcinoma — is divided into stages IA and IB. In stage IA, the cancer is smaller than 2 centimeters in diameter and has not spread to lymph nodes or other parts of the body. In stage IB, the cancer is 2 centimeters or larger in diameter and has not spread to …   English dictionary of cancer terms Merkel cell carcinoma — Rare and highly malignant skin tumour that arises from neuroendocrine cells with features of epithelial differentiation …   Dictionary of molecular biology 18+ © Academic, 2000-2024 Contact us: Technical Support, Advertising Dictionaries export, created on PHP, Joomla, Drupal, WordPress, MODx. Mark and share Search through all dictionaries Translate… Search Internet Share the article and excerpts Direct link … Do a right-click on the link above and select “Copy Link”