for CU Dentistry students

1. EMBRYOLOGEMBRYOLOG
YY
Dr Marwa Magdy Saad Abbass
PhD Oral Biology
Dr Heba Hakam
Associate professor Oral biology

2. During face development
There is a common oro-nasal cavity occupied
by developing tongue
Separation between oral and nasal cavities
occurs by developing of the palate

3. PALATEPALATE
DEVELOPMENTDEVELOPMENT

4. Primary
palate
Secondary
palate
Palate is formed of:
Primary palate and Secondary palate

5. The primary palateThe primary palate
5th-
6th
wiu5th-
6th
wiu

6. primary palateprimary palate
• Called primary as it
forms initial separation
between oral and nasal
cavity
• It is formed of the
posterior part of the
intermaxillary segment
between incisors
and incisive fossa
Primary
palate

7. Derivtives of the intermaxillary segment:
2- The anterior portion of the maxilla carrying the incisor teeth
(pre-maxilla).
1- Middle portion of the upper lip
(philtrum)
3-The anterior portion
of the palate called
(primary palate).

8. DevelopmentDevelopment
of the nasal cavityof the nasal cavity

9. Medial nasal process
The nasal pit deepens to form a nasal sac which is
separated from the stomodeum by the naso-buccal
membrane double layer ectodermal membrane.
Lateral nasal process
Nasal pit
At 6 WIU

10. * The naso-buccal membrane breaks down to form
the nasal duct which communicates the primitive
nasal & oral cavities. (nasal sac and stomodeum)

11. * The ectoderm of the roof of the primitive nasal
cavity differentiate into olfactory epithelium

12. 08- The development of the face and palate - YouTube.mp4

13. The secondary palateThe secondary palate
6-9 W.I.U6-9 W.I.U

14. 1- The oral cavity increase in height and the nasal
septum grows backward.
2- Oral cavity communicates with nasal cavity.
3- The tongue is narrow and high and it reaches the nasal
septum .
At 6 W.I.UAt 6 W.I.U
4- The roof of the oral cavity is
horse shoe shape formed of:
•Primary palate anteriorly
• Horizontal surface of maxillary
process laterally

15. 5- Each maxillary process sends 2 downwards, vertical
palatine processe on the sides of the tongue.
Tongue
Max.
Process
Nasal
Septum
Palatine
process Mandibular
arch
Fore
Brain

16. Primary palate
Palatine process
Nasal septum

17. Nasal
Septum
Palatine
process
Primary palate
Max.
Process

18. 6- At 9 wiu, due to rapid growth of mandible, the tongue
move down ward.
7- Then the 2 vertical palatine process become horizontal.

19. tongue

20. 1- Contractile fibroblasts in the palatine processes.
2- Differential growth (oral side of the process grows
faster than nasal side).
3- Mesodermal proliferation at the angle between
palatine process and maxillary process from oral side.
The 2 vertical palatine process become horizontal in position
due to :
4- Growth of the mandible and downward movement of
the tongue.

21. Development Animation - Palate 2 - Embryology.flv

22. 8- The 2 palatine shelves will unite together and
with the primary palate and with nasal septum in Y
shape.
9-The direction of union start at center of the Y and
extend anteriorly and posteriorly.

23. Fusion of palatine processes

24. Anteriorly to fuse the 1ry palate and 2 palatine
processes
Posteriorly to fuse the 2 palatine processes
together and with the nasal septum

25. Nasal septum
Palatine
process
Palatine
process

26. Sec. palate gives rise to:
most of the hard palate
soft palate&
uvula

27. For fusion of palatine shelves to occur and for fusion
of any other processes, it is necessary to eliminate
their epithelial covering at the line of fusion
Mechanism of fusion of the 2 palatine process :
Then mesoderm will invade the line of fusion.

28. 1- Cessation of DNA synthesis in the epithelial cells at
line of fusion 24- 36 hours before contact
3- The basal epithelial cells have carbohydrate rich cell
coat.
5- Mesodermal proliferation invade the midline seam
which thin and breakdown into discrete islands
6- The islands lose their basal lamina and undergo
mesenchymal transformation or phagocytosed
Mechanism of fusion of the 2 palatine process :
2- sloughing of surface epithelial cells by apoptosis
(Apoptosis is physiological cell death)
4- fusion of the basal epithelial cells of the 2 processes to
form midline seam.

29. Cleft palate:
• Malunion between two 1ry palate, palatineMalunion between two 1ry palate, palatine
processes andprocesses and nasal septum.
• It may beIt may be unilateral or bilateral.unilateral or bilateral.
• May beMay be anterior or posterioranterior or posterior

30. Posterior cleft palate
(Median)
Unilateral complete
lip and palate
Bilateral complete
lip and palate

31. Unilateral, anterior Bilateral, anterior Bifid uvula.Bifid uvula.

32. CLEFT LIP AND PALATE.mp4

33. THANK YOU