DEZVOLTAREA CEFALICA (1)

8/11/2019 DEZVOLTAREA CEFALICA (1)

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DEZVOLTAREA FETEI


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DEZVOLTAREA PALATULUI


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Development of Palate

The palate develops from two stages:

Primary palate

Secondary palate

Palatogenesis begins at the end of the fifth week andis completed at twelfth week (5------12 )

The critical period of the palate development is from

the endof the sixthweek until the beginningof ninth

week (6 ------ 9) 12Prof. Makarem


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Primary Palate

Early in the sixth week theprimary palate or median

palatine process begins to develop from theintermaxillary segment of the maxilla

Initially this segment is formed by merging of the

medial nasal prominences

The primary palate forms the premaxillary part ofthe maxilla

It represents only a small part of the adult hardpalate

(2 Medial nasal prominences >>>>intermaxillarysegment .>>>>>>>>>-primary palate).

13Prof. Makarem


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Initially the lateral

palatine processes or

palatalshelvesproject

inferomedially on

each side of the

developing tongue

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Palatine processes alsofuse with the nasalseptum and the posteriorpart of the primary palate

The nasal septumdevelops as a downgrowthfrom internal parts of the

merged medial nasalprominences

The fusion between the

nasal septum and thepalatine processes beginsanteriorly during the ninthweek and is completedposteriorly by the twelfthweek 19Prof. Makarem


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Palatal shelves move medially andfuse with the nasal septum.

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Bone gradually develops in theprimary palate, forming thepremaxillary part of the maxilla,

which lodges the incisor teeth

Concurrently bone extends fromthe maxillae and palatine bones

into the lateral palatineprocesses to form the hardpalate

The posterior part of theseprocesses do not ossified.

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They extend posteriorly

beyond the nasal septum

and fuse to form the softpalate.

Its soft conical projection is

called uvula

The median palatine raphe

indicates the line of fusionof the lateral palatine

processes

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25Prof. Makarem


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DEZVOLTAREA DINTILOR


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Dezvoltarea dinilor

Lamina dentalis : ngroareaectodermului ce acopermaxilaimandibula n S 7; prolifereaz n mezenchimul subiacent iformeaz 10 muguri ai dentiiei deciduale, organeleadamantoblaste(ameloblaste)

Mugurele smaluluinvagineaz sub form de cup (statuscappalis), apoi de clopot (status campanalis);

se difereniaz n strat extern (epithelium enameleum externum) iunul intern (epithelium enameleum internum)

Mezenchimul condensat n interiorul clopotului formeaz

papilla dentis, celulele periferice se difereniaz nodontoblaste.


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Dezvoltarea dinilor

Histodiferenierean ameloblasteiodontoblasteeste indusde interaciuneaepitelio-mezenchimatoas

Ameloblastele stratului intern formeaz coroana dintelui,stratul extern formeaz cuticula dintelui (membrana

Nasmyth), care regreseazdupnatere. Mezenchimul din jurul mugurelui dentar formeaz sacculus

dentis i se difereniaz n lamina cementoblastica (secretcimentul), lamina periodontoblastica (ligamenteleperiodontale), lamina osteoblastica (osul alveolar).


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DEZVOLTAREA CEFALICA (1)

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