Plate Development

Question 1

When the primary palate formed ?

Answer 1

4-5th week

Question 2

The primary palate formed by

Answer 2

Merging of two media nasal processes

Question 3

The merging of the two medial nasal processes result formation of

Answer 3

1-primary palate
2-middle portion of the nose
3- middle portion of the upper lip
4-the interior part of Maxilla

Question 4

Where the nasopalatine canal formed?

Answer 4

Posterior part of the primary palate in 9-13th week

Question 5

What happened in 28th week?

Answer 5

intramembranous ossification of the primary palate takes place through two pre-maxillary ossification centers

Question 6

What happened in 1-2 years?

Answer 6

pre-maxillary suture completely fuses with secondary palate

Question 7

When the secondary palate appears?

Answer 7

6-8th week

Question 8

The secondary palate s formed by?

Answer 8

fusion of the two lateral palatal shelves

Question 9

What are the palatal shelves?

Answer 9

medial extensions of the maxillary processes

Question 10

Where the palatal shelves developed?

Answer 10

behind the primary palate

Question 11

The mesenchyme of palatal shelves originates from

Answer 11

Neural crest

Question 12

What happened in 6th week ?

Answer 12

-Nasal cavities are separated by a primary nasal septum and from the oral cavity

-anteriorly by the primary palate

-posteriorly communicate with oral cavity to form the oro-nasal cavity

-Secondary nasal septum grows down from the roof of stomodeum behind the primary nasal septum

Question 13

What happened in 7th week ?

Answer 13

-The oral part of the oronasal cavity is completely filled by
the developing tongue

-The palatal shelves grow vertically and lie on both sides of the tongue

Question 14

What happened in 8th week?

Answer 14

-The tongue descends

-The two palatal shelves elevates over the developing tongue
and become horizontal

-This elevation is facilitated mostly by descending of the
tongue and shelf elevation force

-Descending of the tongue could be related to growth
of the mandible or change in the shape of the tongue

-The elevation of palatal shelves is produced through
the turgor pressure following hydration of the extracellular matrix (hyaluronan glycosaminoglycan)

Then the palatal shelves meet each other to form the secondary palate, and then contact from above the secondary nasal septum and anteriorly the primary palate

-Complete fusion occurs when the midline epithelial seam breakdown by apoptosis and redifferentiation of the epithelial cells which assume fibroblast-like features a mechanism known as epithelial-mesenchymal transition

-The closure of the secondarym palate proceeds gradually from the primary palate in a posterior direction

Question 15

What happened in 12th week?

Answer 15

-The ossification of the palate starts at 8th week of intrauterine life and completed by the 12th week of intrauterine life

-Myogenesis (means muscle development and growth)
occurs in the posterior third of the palate giving rise to the soft palate

Question 16

Ossification of the secondary palate is achieved through intramembranous ossification in 4 centers:

Answer 16

-Two maxillary centers: lies above the developing deciduous canine tooth germ

-Two palatine centers: in the region forming the future perpendicular plate of the palatal bone

Question 17

Remnants of epithelial that covers the palatal shelves
after fusion of the shelves may result in:

Answer 17

median palatine cyst

Question 18

Remnants of nasopalatine duct give:

Answer 18

rise to nasopalatine duct cyst

Question 19

Cleft of primary palate:

Answer 19

failure of primary palate to fuse with lateral palatal shelves anteriorly, and with secondary palate, posteriorly

Question 20

Cleft of secondary palate:

Answer 20

failure of fusion of the two lateral palatal shelves

Question 21

What is Torus palatinus?

Answer 21

Are localized bony overgrowth consist of compact bone formed irregularly on the midline of the palate