Morphogenesis of the Primary and Secondary Palate

Pourtois, Michel

doi:10.1016/b978-0-12-648350-5.50010-3

Cited by 55 publications

(16 citation statements)

References 5 publications

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“…This agrees with the study by Waterman and Meller (19731, who observed that in the hamster the nasal and oral epithelia near the choanal pit were completely separated from each other by mesenchyme. However, these observations seem to conflict with those of Pourtois (1972) and of Gaare and Langman (1977), who indicate that in the mouse the nasal fin (Hochstetter's membrane) is continuous with the oronasal membrane. Studies using serial thin-section reconstruction correlated with scanning electron microscopy are presently underway in our laboratory to resolve this question.…”

Section: Discussionmentioning

confidence: 71%

The formation of the primitive choanae and the junction of the primary and secondary palates in the mouse

Tamarin

1982

Am. J. Anat.

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This study has followed the development of the primary choanae in the mouse and has shown that they originate at the developmentally strategic position of junction between the primordia of the primary and secondary palates and that this basic anatomic relationship is maintained throughout further development. Involution of the oronasal membrane begins late in the 11th day (stage 19) with the formation of interstitial gaps. The gaps enlarge and coalesce so that a completely patent opening between nasal passage and stomodeum is established by 13 days (stage 21). The membrane consists of two layers of simple squamous epithelium which become separated as involution progresses. The form of the choanal antrum changes from a simple funnel-shaped ellipse early in the 13th day to a complex slitlike opening within the following 24 hours. This coincides with the completion of a definitive primary palate and the enlargement and elevation of the shelves of the secondary palate. The maturation of the incisive papilla and interchoanal columella is related to the final stages of choanal morphogenesis. Thus, by stage 22 (14 days) the shape of the primary choanae and their anatomic relationship to the primary and secondary palates are established, and they remain essentially unchanged in later stages.

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Section: Discussionmentioning

confidence: 71%

The formation of the primitive choanae and the junction of the primary and secondary palates in the mouse

Tamarin

1982

Am. J. Anat.

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“…As in the mouse (Peterková et al 1987;Sakamoto et al 1989), the rat (Thomas and Rossouw 1991), and the European pine vole (Buchtová et al 2003), three antemolar ridge primordia were initially formed in the hamster. At this early stage, the developing palatal ridges could stiffen the lateral palatal processes, as suggested by Pourtois (1972). The intermolar ridges of the hamster did not develop until the lateral palatal processes had shifted into horizontal position.…”

Section: Time Programme Of Palatal Ridge Developmentmentioning

confidence: 81%

Section: Oral Cavity Proliferation Embryo Foetus Developmentmentioning

confidence: 99%

“…Palatal ridges contain tactile and taste receptors, so they have also a sensory function (Scott and Symons 1967;Luke 1980). In embryos, they are assumed to stiffen and strengthen the palatal processes during formation of the secondary palate (Pourtois 1972;Brinkley and Vickerman 1982;Luke 1984;Bulleit and Zimmerman 1985).Palatal ridge development has been studied mainly in the mouse. Primordia of the rugae palatinae are as well as dental and vestibular laminae derivatives of the odontogenic epithelial zone, an epithelial placode on the oral surface of the developing maxilla that can be recognised in ED 12.0 mouse embryos (Peterková 1985).…”

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confidence: 99%

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Morphogenesis of Palatal Ridges in the Golden Hamster (Mesocricetus auratus, Rodentia)

Buchtová¹,

Matulová²,

Witter³

et al. 2005

Acta Vet. Brno

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Rugae palatinae (RP) -transversal mucosal ridges of the mammalian palate -are assumed to play a role during closure of the palate in embryos. The aim of this study was to assess the morphogenesis of palatal ridges in the golden hamster (Mesocricetus auratus, Rodentia) by light and scanning electron microscopy. Cell proliferation was detected by immunohistochemical staining of proliferating cell nuclear antigen (PCNA). In the hamster, three to four antemolar and three intermolar ridges were formed. In ED 11.0 (ED -embryonic day) embryos, RP1 and RP3 were at the epithelial thickening stage, RP2 was a primitive ruga in the rostral part of the palatal processes. In the caudal part of the palate, an epithelial placode represented the prospective RP4-RP7. At ED 12.5, the closed secondary palate bore six ridge primordia. Only RP2 protruded distinctly into the oral cavity. At ED 13.0-14.5 and ED15.0-15.5, the mesenchymal core of the antemolar and intermolar ridge primordia, respectively, started to develop. Strikingly, a local increase of proliferation activity does not seem to be the main process involved in palatal ridge formation and elevation. Although the palatal ridge formation and elevation is based on tissue volume enlargement, strikingly, the proliferation activity was higher in the interrugal epithelium than in the ridge primordia. Rather than the epithelial proliferation activity increase, the change in orientation of mitotic spindles of dividing cells seems to be a reason of palatal ridge formation. Oral cavity, proliferation, embryo, foetus, developmentPalatal ridges (rugae palatinae) are more or less transversal mucosal ridges of the hard palate, which are covered by a cornified stratified squamous epithelium. Number and arrangement of the palatal ridges is specific for the respective mammalian species.Palatal ridges have an important function during pre-and postnatal development. They help to transport the food within the oral cavity (Zietzschmann et al. 1943) and take part in grinding the food between tongue and hard palate (Eisentraut 1975). Palatal ridges contain tactile and taste receptors, so they have also a sensory function (Scott and Symons 1967;Luke 1980). In embryos, they are assumed to stiffen and strengthen the palatal processes during formation of the secondary palate (Pourtois 1972;Brinkley and Vickerman 1982;Luke 1984;Bulleit and Zimmerman 1985).Palatal ridge development has been studied mainly in the mouse. Primordia of the rugae palatinae are as well as dental and vestibular laminae derivatives of the odontogenic epithelial zone, an epithelial placode on the oral surface of the developing maxilla that can be recognised in ED 12.0 mouse embryos (Peterková 1985). The development of individual palatal ridges of the mouse starts at ED 13.0.Step by step eight rugal primordia occur. The

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“…Thus it is unlikely that the epithelial and mesenchymal cytoplasmic projections and contacts between them, as observed in the present study, develop for nutritional purposes. Epithelial-mesenchymal communications have been considered to play an important role during normal development in determining the differentiation and fate of the palatal epithelium (Pourtois, 1972;Tyler and Koch, 1977;Shah, 1984). Since the injured epithelial and mesenchymal cells may have deviated from the normal path of differentiation, it is possible that they prepared themselves for a new role in the cleft palate by communicating with one another.…”

Section: Discussionmentioning

confidence: 99%

Gross and cellular analysis of 6‐mercaptopurine‐induced cleft palate in hamster

Burdett

Shah

1988

Am. J. Anat.

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The present study analyzes the morphological, histochemical, and ultrastructural aspects of the pathogenesis of 6-mercaptopurine (6MP)-induced cleft palate in hamster fetuses. Gross and light microscopic observations indicated that 6MP stunts the growth of vertical palatal shelves and thus induces cleft palate. Ultrastructural analysis showed that, in contrast to controls, 6MP-induced alterations were first seen in the mesenchymal cells 24 hr after drug administration. The initial alterations were characterized by swelling of the nuclear membrane. During the next 12 hr, lysosomes were seen first in the mesenchymal cells and then in the cells of the medial edge epithelium (MEE) of the developing palatal primordia. The appearance of lysosomes was temporally abnormal and was interpreted as a sublethal response to 6MP treatment. Subsequently, the nuclear alterations and the lysosomes diminished; and 48 hr after 6MP administration, they were absent from the palatal tissues. Ninety hours after 6MP administration, unlike the controls (in which the palatal shelves were already fused), changes were seen at the epithelial-mesenchymal interface in the developing cleft palatal shelves. These changes were characterized by breakdown of the basal lamina and epithelial-mesenchymal contacts. Eventually, at term, the MEE of the vertical shelf stratified. It was suggested that 6MP affected cytodifferentiation in the palatal tissues during the critical phase of early vertical shelf development and thereby induced cleft palate.

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Morphogenesis of the Primary and Secondary Palate

Cited by 55 publications

References 5 publications

The formation of the primitive choanae and the junction of the primary and secondary palates in the mouse

The formation of the primitive choanae and the junction of the primary and secondary palates in the mouse

Morphogenesis of Palatal Ridges in the Golden Hamster (Mesocricetus auratus, Rodentia)

Gross and cellular analysis of 6‐mercaptopurine‐induced cleft palate in hamster

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