Development of the palate

Question 1

when does the formation of the palate occur

Answer 1

weeks 6-12

Question 2

initially there is a common oronasal cavity.

the primary palate is derived from what?

Answer 2

fused medial nasal prominences and intermaxillary segment

Question 3

bone formation in the primary palate

?? turn into ? which deposit ?, trapped ? become ? which differentiate and form the ? of the primary palate

Answer 3

mesenchymal cells
osteoblasts
osteoid
osteoblasts
osteocytes
bone

Question 4

what happens during week 6 of palate formation?

Answer 4

ectomesenchymal cells migrate to form nasal septum (at top) and palatal shelves (middle)

Cells proliferate, make matrix and fill the gap

Question 5

what happens during week 7 of palate formation?

Answer 5

ectomesenchymal cells migrate to form nasal septum (at top) and palatal shelves (middle)

Cells proliferate, make matrix and fill the gap

Question 6

what happens during weeks 8-12 of palate formation?

Answer 6

tongue withdraws down

palatal shelves flip up into horizontal position (males can be week 7)

mesenchyme flows into shelves and lays matrix

lateral plates grow, meet in the midline and fuse front to back -> secondary palate

Question 7

give two explanations for palatal shelf elevation

Answer 7

extrinsic forces
intrinsic forces

Question 8

what extrinsic forces are involved in palatal shelf elevation?

Answer 8

Tongue withdrawal due to head lifting from cardiac plate, Meckel’s cartilage growth and increased height of nasal cavity

Question 9

what intrinsic forces are involved in palatal shelf elevation?

Answer 9

hydration of ECM (hyaluronin)
mesenchymal cells contracting
collagen fibres

Question 10

overview of formation of the secondary palate

Question 11

overview of formation of the secondary palate

Question 12

what is the role of the secondary palate?

Answer 12

Separate the nasal airway and oral cavity

Important for mastication, sensation and speech

Question 13

why dont the palatal shelves stick to the tongue?

Answer 13

Epithelial adhesion -> specific sticky surface glycoproteins that will only stick to a similar glycoprotein

Question 14

Knocking out ? gives cleft palate in mice

Answer 14

TGFB3

Question 15

in fusion of the palate, what are the three theories for disintegration of the midline to get one fluid entity?

Answer 15

Epithelial to mesenchymal transition

Apoptosis of epithelial cells

Migration to the nasal or oral edge

Question 16

failure of palatal shelf fusion leads to what? what gene is this linked to?

Answer 16

partial or complete cleft palates

hyaluronan synthase genes

Question 17

Epithelial remnants as epithelial cells either don’t migrate, apoptose or transition into mesenchyme, leads to what?

Answer 17

epithelial crests that have cystic potential leading to pain in the roof of the mouth