Merkel cell

Source: Wikipedia, the free encyclopedia.
Merkel cell
Merkel cells (shown in blue) are located in the basal epidermal layer of the skin.
Details
LocationSkin of vertebrates
FunctionLight touch sensation
Identifiers
MeSHD018862
NeuroLex IDnifext_87
Anatomical terms of neuroanatomy

Merkel cells, also known as Merkel-Ranvier cells or tactile epithelial cells, are oval-shaped

epithelial
in origin.

Structure

Merkel cell.

Merkel cells are found in the skin and some parts of the mucosa of all vertebrates. In mammalian skin, they are clear cells found in the

rete ridges.[4]

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. They react to low vibrations (5–15 Hz) and deep static touch such as shapes and edges. Due to a small receptive field (extremely detailed info) they are densely present in areas like fingertips; they are not covered (shelled) and thus respond to pressures over long periods.

Developmental

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,[5] but experiments in mammals now demonstrate an epidermal origin.[6][7]

Function

The German anatomist Friedrich Sigmund Merkel referred to Merkel cells as Tastzellen or "touch cells". Until recently this proposed function was controversial and hard to prove, due to the close physical association of Merkel cells with sensory nerve endings. However, recent work in mice and other model organisms demonstrates that Merkel cells intrinsically transform touch into electrical signals that are transmitted to the nervous system.[8] Merkel cells express PIEZO2, a mechanosensitive ion channel that responds to mechanical forces. Mice in which Piezo2 is knocked-out specifically in skin cells, but not sensory neurons, show decreased behavioral responses to gentle touch.[9]

Merkel cells are sometimes considered

neuroendocrine function.[10]

Susceptibility to malignancy

Although uncommon, these

Merkel cell carcinoma—an aggressive and difficult to treat skin cancer.[11][12]

See also

References

  1. ISBN 978-0-12-370880-9
    .
  2. ISBN 978-0-12-801654-1
    .
  3. ISBN 978-0-07-184270-9
    .
  4. PMID 12552639.[dead link
    ]
  5. ISBN 978-3-540-00374-8
    . Retrieved 2 May 2010.
  6. PMID 19782676
    .
  7. PMID 19786578
    .
  8. PMID 24717432
    .
  9. PMID 24717433
    .
  10. ISBN 978-0-12-386457-4
    .
  11. PMID 28174236
    .
  12. PMID 24574661
    .

External links

Wikimedia Commons has media related to Merkel cell.