1. Kharkov National Medical University
LECTURE for dentistry students
Department of
Histology, cytology and embryology

2. MICROMORPHOLOGY AND EMBRYOLOGY OF THE ORAL CAVITY

3. FACE AND ORAL CAVITY ORGANS DEVELOP FROM MESENCHYME, ECTODERM AND ENDODERM
On the 3-4-th week the stomatodaeum (oral bay - ectodermal invagination ) is formed.
This will fuse with the gut through oropharyngeal membrane.

4. Oropharyngeal
Membrane Amnion gut
Stomatodaeum Yolk sac

6. Pharynx wall forms 4 thickenings –pharyngeal arches

7. 1. Each consists of mesenchyme, outer ectoderm and inner endoderm.
2. Arches mesenchyme provides the skeletal muscle and c.t.
3. They form: 1) face, nasal cavities, ) mouth, larynx, ) pharynx, and neck.

9. Development of oral cavity begins with the formation of frontal process over the oral bay and
growth of the 1-st ph. arch, which divides on:
– maxillar and mandibular processes

10. Frontal
process
Ectoderm
Pharyngeal Pouches

11. Frontal Process
Maxillary
Mandibular

12. In the frontal process are formed olfactory pits.
They divide f.p. on medial and lateral nasal processes
– Latter fuse with maxillar and mandibular processes and
nose and lips appear

13. Olfactory pit NASOMEDIAL PROCESS Nasolateral process
MAXILLARY PROCESSES
grow to meet just off the midline, which is occupied by the fusing medial nasal processes
FRONTONASAL REGION gets back by merging nasomedial processes
FACE

14. 7-w/19mm EMBRYO NASOMEDIAL PROCESS EYE MAXILLARY PROCESS MOUTH
MANDIBULAR PR.
HYOID BONE
LARYNGEAL CARTILAGES
FACE

16. This causes nursing problem for the new born.
Malformation
1.Clefts involving the upper lip
2.Unilateral and 3.Bilateral cleft lip result if maxillary and medial nasal processes do not fuse.
4. Cleft palate leaves the nasal and oral cavities connected.
This causes nursing problem for the new born.

17. FACIAL DEFECTS: UNILATERAL CLEFT LIP OBLIQUE FACIAL CLEFT
MEDIAN CLEFT JAW
UNILATERAL MACROSTOMIA mouth too wide (microstomia - too small)
MEDIAN CLEFT LIP Nose may also be cleft
UNILATERAL CLEFT LIP
FACE

18. Bilateral Facial clefts and bilateral cleft lip
Cleft Upper lip
“hairlip”

19. PALATE developes by fushion of maxillar processes

20. PALATAL DEFECTS I: Partial failures to fuse
UNILATERAL CLEFT LIP
ANTERIOR CLEFT PALATE Incomplete & Unilateral
CLEFT UVULA
Lateral palatines

21. PALATAL DEFECTS II: Failures to fuse
COMPLETE UNILATERAL ANTERIOR CLEFT Palate & Lip
POSTERIOR
CLEFT PALATE
Can occur independently; can be partial; anterior can be bilateral
PALATE

22. Sources of Tongue development
ARCH I II
III IV
ARCH I
ARCH III
Terminal sulcus
TONGUE

24. TONGUE MALFORMATIONS I
ARCH I II
III IV
LATERAL LINGUAL SWELLINGS
Failure of these to fuse properly causes a DEEP MEDIAL SULCUS or at worst a SPLIT TONGUE
Overgrowth - MACROGLOSSIA
Undergrowth - MICROGLOSSIA
TONGUE

25. ORAL CAVITY IS LINED BY MUCOSA, CONSISTS OF
STRATIFIED NONKERATINIZED EPITHELIUM
AND C.T. LAMINA PROPRIA
FUNCTIONS:
1. PROTECTIVE
2. SECRETORY
3. SENSORY

26. TONGUE ORAL STRUCTURES Sagittal view TOOTH LIP HARD PALATE SOFT PALATE
SALIVARY GLANDS
ALVEOLAR BONE
+ CHEEK
GUM

27. MASTICATORY (CHEWING)
ORAL MUCOSAE: Classification
MASTICATORY (CHEWING)
Epithelium undergoes keratinization
HARD PALATe
GINGIVAe
SPECIALIZED
DORSAL LINGUAL
LINING (COVERING)
LABIAL
BUCCAL
ALVEOLAR
SOFT PALATAL

28. LIP 1. HAIRY SKIN anterior 2. RED MARGIN VERMILION transitional
3. LABIAL MUCOSA thick inner
GLAND mucous
1. HAIRY SKIN
anterior
MUSCLE

29. } GUM (GINGIVA) TOOTH Gingival sulcus/ crevice/FISSURE FREE GINGIVA
ATTACHED GINGIVA
c.t. }
Epithelial attachment
TOOTH
Gingival sulcus/ crevice/FISSURE

30. 3. Glandular zone MUCOUS GLANDS
HARD PALATE: Cross-section
PALATE BONE why it is hard!
Periosteum
2. Palatal seam
1.Fatty zone – anterior
3. Glandular zone MUCOUS GLANDS
- posterior
STRATIFIED SQUAMOUS EPITHELIUM slightly-keratinized

31. TONGUE - dorsum CIRCUMVALLATE PAPILLA FUNGIFORM PAPILLA
TONSILS
CIRCUMVALLATE PAPILLA
Trench
FUNGIFORM PAPILLA
FILIFORM PAPILLAE
General sensation
Taste bud
FOLIATE PAPILLAE on the lateral t.

32. SALIVARY GLANDS - major & minor
Parotid
Sub-mandibular
Sub-lingual
MINOR
Labial. Buccal.
Lingual. Palatal

33. SALIVA – Functions Anti-microbial materials PROTECTION Mastication
ALIMENTARY
Mastication
Swallowing
Digestion
OTHER
Vocalization
Excretion
Epithelial lubrication
Anti-microbial materials
For tooth: Rinsing Buffering Mineralization

34. Mucins (glycoproteins) Antibodies IgAs
MATERIALS:
Water
Mucins (glycoproteins) Antibodies IgAs
Lysozyme Defensins
Ions - tooth mineral
Amylase Iodine

35. } General duct Lobule SCHEME OF SALIVARY GLANDS Interlobular duct
SECRETORY UNITS }
General duct
Lobule
Interlobular duct
STRIATED duct
Intercalated ducts
See SALIVA Powerpoint

36. 1. SEROUS ALVEOLUS 2. MUCOUS TUBULE BL 3. MIXED UNIT SEROUS DEMI-LUNE
MYOEPITHELIAL CELL
SEROUS DEMI-LUNE BL
1. SEROUS ALVEOLUS
3. MIXED UNIT
with

37. PAROTID GLAND (serous)
SEROUS ACINi
STRIATED DUCT
INTERCALATED DUCT
INTER LOBULAR DUCT

38. SUBMANDIBULAR GLAND (sero-mucous)
SEROUS ACINi
INTRA LOBULAR DUCT
INTER LOBULAR DUCT
A FEW MIXED
units
SEROUS demilune

39. SUBLINGUAL GLAND (muco-serous)
INTER LOBULAR DUCT
MIXED MUCOUS TUBULES
SEROUS demilune
MUCOUS LE
STRIATED DUCT (few)