palate formation part 1 and 2

Question 1

what weeks is the palate formed?

Answer 1

6-12

Question 2

what is the function of the primary palate?

Answer 2

DEMARCATES nasal and oral cavities NOT separate

Question 3

what it the primary palate derived from?

Answer 3

medial nasal prominences and inter maxillary segment

Question 4

what does the secondary palate separate?

Answer 4

nasal and oral cavity

Question 5

what are the functions of the secondary palate?

Answer 5

-formation of food bolus
-taste and texture
-speech

Question 6

what happens on week 6 of secondary palate formation?

Answer 6

mesenchymal cells migrate to form nasal septum
mesenchymal cells migrate to form lateral shelves of palate
-tongue forms upwards

Question 7

what happens in week 7 of secondary palate formation?

Answer 7

tongue takes up a lot of room- and lateral shelves of palate are forced to move down side of tongue- BUT do not attach to tongue (diff glycoproteins on epithelium)

Question 8

what happens in week 8 of secondary palate formation?

Answer 8

tongue moves downwards and shelves elevate rapidly and slowly move towards each other to the midline

Question 9

when does elevation happen in males to females?

Answer 9

males- week 7
females- week 8

Question 10

what extrinsic factor may force the tongue downwards?

Answer 10

-head lifts from cardiac plate
-nasal height increases
-meckels cartilage formation moves tongue

Question 11

what are 3 reasons which may cause intrinsic elevation of palatal shelves?

Answer 11

1- hyaluran (GAG) can bind 10 x its weight in water- turgid and drives elevation

2- shortened mesenchymal have contractile features which may help elevate shelves

3-blood flow

Question 12

as the shelves grow towards each other- what is the midline known as?

Answer 12

epithelial midline

Question 13

in what way does the palate begin to “zip”?

Answer 13

from anterior to posterior

Question 14

how long does it take for the palate to fuse ?

Answer 14

4 weeks

Question 15

is secondary palate formation true fusion of fake fusion?

Answer 15

true fusion

Question 16

what must happen to the midline epithelium once fused?

Answer 16

it must disintegrate

Question 17

what would happen If the midline epithelium did not disintegrate?

Answer 17

weak palate- would eventually split

Question 18

what are the 3 theories of midline epithelial disintegration?

Answer 18

1- epithelium mesenchymal transition where epithelial become mesenchyme cells that go on to form facial structures
2-apoptosis- programmed cell death
3- migration to nasal and oral edges to be part of oral epithelium

Question 19

what causes fusion problems?

Answer 19

due to epithelial midline remnants

Question 20

what is the most common congenital disease?

Answer 20

cleft palate/cleft lip

Question 21

what causes cleft palate/cleft lip in percentages?

Answer 21

20%- mutagenic change
20%unknown

Question 22

what are the risk factors of CL/CP?

Answer 22

smoking
drugs
alcohol
rubella (virus)
increase in vit a
decrease in folate

Question 23

explain the TGF3-beta knockout mice research

Answer 23

tgf3-beta was knocked out of mice - clefts formed
- HA has 3 enzymes
-ha 1 and 2 have high molecular weight
-ha 3 has low mw
-only ha 3 was stained in knockout mice
-meaning ha 1 and 2 were absent- so not enough molecular weight to elevate shelves