Lens placode
| Lens placode | |
|---|---|
| File:Gray864.png Transverse section of head of chick embryo of fifty-two hours’ incubation. | |
| Details | |
| Precursor | Surface ectoderm |
| Gives rise to | Lens |
| Identifiers | |
| Latin | placoda lentis |
| TA98 | Lua error in Module:Wikidata at line 746: attempt to index field 'wikibase' (a nil value). |
| TH | {{#property:P1694}} |
| TE | {{#property:P1693}} |
| FMA | {{#property:P1402}} |
| Anatomical terminology [[[d:Lua error in Module:Wikidata at line 865: attempt to index field 'wikibase' (a nil value).|edit on Wikidata]]] | |
The lens placode is a thickened portion of ectoderm that serves as the precursor to the lens.
Invagination
[edit | edit source]Invagination is the process of folding in cells. The lens placode invaginates to later develop the lens or lens pit. The development of the lens placode is typically seen between 44 and 50 hours; invagination occurs shortly after at around the 50–55-hour mark. (Mouse)[1]
Both the formation of the lens placode, and the invagination of this to the lens pit are both morphogenetic events.[2]
Cell shape, density, and surface area
[edit | edit source]Chick embryos studies show the lens placode contains a cuboidal to columnar cell shape and that it is not multilayered. Furthermore, the density of the cell appears to double in size once the placode has developed. And while the cell density increases, the surface area is not impacted.[2]
Restricted expansion hypothesis
[edit | edit source]The restricted expansion hypothesis” states that the adhesion of the ectoderm cells to the matrix is a key factor in the lens placode formation. This adhesion is accompanied by cell proliferation, which also impacts crowding and cell elongation.[2]
Transcription factors
[edit | edit source]Pax6 is a transcription factor that is essential to the development of the lens placode. More specifically, it is needed for the surface ectoderm to fully develop. Pax6 has been identified as a necessary transcription factor for the thickness of the lens placode.[3]
SOX2 is a transcription factor that works alongside Pax6 to develop the lens placode. They maintain the same protein levels in the ectoderm. Therefore, SOX2 and Pou2f1 are involved in the development of the lens placode.[4]
See also
[edit | edit source]References
[edit | edit source]- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ a b c Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
Public domain This article incorporates text in the public domain from the 20th edition of Gray's Anatomy (1918)
External links
[edit | edit source]- eye-008—Embryo Images at University of North Carolina
- Human Anatomy Chapter 18 – Embryology Atlas
- Neuroembryology: Development of the Eye: Lens Placode Appears (4 weeks)
Lua error in mw.title.lua at line 392: bad argument #2 to 'title.new' (unrecognized namespace name 'Portal'). Lua error in Module:Authority_control at line 153: attempt to index field 'wikibase' (a nil value).
