nasal placodes

na·sal plac·odes

paired ectodermal placodes that come to lie in the bottom of the olfactory pits as the pits are deepened by the growth of the surrounding medial and lateral nasal processes.
Synonym(s): olfactory placodes

na·sal plac·odes

(nāzăl plakōdz)
Paired ectodermal plates that come to lie in bottom of olfactory pits as they deepen by growth of surrounding medial and lateral nasal processes.
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References in periodicals archive ?
The presence of cellular debris resulting from cell death in the deepest aspects of the invaginating nasal placodes, as well as overall growth retardation of the facial prominences, leads to inability of the facial prominences to contact and fuse (rev by Sulik, 1988).
It is well established that at the time of consolidation of the facial processes there is a concurrent program of spontaneous cell death (PCD) involved in the removal of the epithelial debris from the developing nasal placode. When this PCD is more extensive than necessary and repair of mesenchyme is disturbed, a weakness develops in the forming lip and alveolus.
The literature of embryology describes that the mesenchyme covering the caudal surface of the forebrain proliferates with surface ectoderm to form frontonasal process and the two ectodermal thickenings (nasal placodes) arise on each side of the depedent part of the frontonasal process (Johnson, 1989).
The nasal placodes (olfactory placodes) arise from the medial aspect of the lower portion of the frontal prominence, and the lens placodes arise from the lateral aspect of the lower portion of the frontal prominence.
The nasal placodes develop as early as the third week of gestation.