oral mucosa chapter for dental students

1. Dr: Mahmoud 3mmar
Mobile: 0106 39 700 30
F.B: m.3mmar9428@yahoo.com

2. Oral mucosa
( lecture 1 )
Contents of chapter:-
1) definition.
2) functions. (protection , sensation , secretion).
3) organization. (outer vestibule & oral cavity proper).
4) classification. (masticatory & lining & specialized).
5) histological str. (oral epith.,lamina propria , basement memb)

3. Oral mucosa: (epith + C.T) its structurally ,
functionally transitional zone between the skin &
GIT , exhibits features of both.
 its like GIT in : its bathed in fluid & have high rate
of turnover.
 like skin in : its possesses a stratified epith. Which
is keratinized in many places thus
prevents , limits diffusion across
both direction.

5. skinOral mucosa
notmoistmoisture
sebacioussalivaryglands
foundnotHair follicle
morelessfirmness
lessmoreSurface
smoothness
lessdeeply coloredcolor

6. Human
tissues
1) epithelial
3) mascular
4) nervous
2) connective

7. General features of epithelial tissue:
1) cells rests on basement membrane. & have
free surface
2) cells adhere to each other in one layer or more.
3) cells a-vascular but have nerve fibers.
4) cells cover a surface , lined cavity and form glands.
5) basal surface contact the basement membrane while
free surface interface with external environment or
space within the body.

8. Oral mucosa has 2 main tissue component:
1) stratified squamous epith. (oral epith.).
2) underlying C.T layer (lamina propria).
rete-pegs: part of oral epith. Which
interdigitate with C.T papillae.
connective tissue papillae: irregular
upward projection of C.T which inter
face with rete-pegs.

9. Functions of the oral epithelial:-(protection , sensation , secretion ).
1) protection: a- separates ,protect deeper tissues &
organs in oral region from the
environment of oral cavity.
b- its show number of adaptation of
epith , C.T to withstand force of
mastication & it acts as barrier to
microorganism , toxins.

10. 2) sensation: its provide information about events
in oral cavity where as lips , tongue
perceive stimuli outside the mouth.
a) in the mouth receptors respond to
temperature , touch , pain , taste and thirst .
b) tongue has taste buds.
c) reflexes (swalloing , salivation , gagging) are
initiated by receptors in the oral cavity.

11. 3) secretion: major secretion associated with oral
mucosa is saliva from major , minor
salivary glands which maintains a
moist , lubricant surface of the oral
mucosa .
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12. 3-organization:
1) outer vestibule bounded
by lips , checks.
2) oral cavity proper : superior zone
of oral cavity proper formed
by hard & soft palate.
inferior border formed by floor of
mouth , tongue.

13. 4-classification of oral mucosa:
(25%masticatory mucosa & 60%lining mucosa & 15%specialized mucosa).
1) masticatory mucosa: (25%) this parts from oral mucosa
subjected to force of mastication
& pressure
this parts are : 1-Gingiva 2-Hard palate.
*) this parts are rubbery , resistant & keratinized
or para-keratinized stratified squamous epith.

14. 2)Lining mucosa (60%): its presen in areas
which not subjected to high
force but its must be
mobile , distensible .
1.2.3- Its buccal , labial , alveolar mucosa
4.5- floor of mouth & ventral tongue
6- Soft palate.
Its non keratinized stratified squamouth epith.

15. specialized mucosa (15%):its mucosa covering the
dorsal surface of the tongue
and contains different types
of taste buds , papillae and
lingual tonsils , lymph tissues.

16. 5) Histological structure:
Basal cell layer
Prickle cell layer
Granular cell layer
Cornified cell layer
 basal
 intermediate
 superficial
3-Lamina
propria
Stratified squamous
epithelium
Keratinized
Non-
keratinized:
•ortho-keratin.
•para-keratin.
Papillary
layer
Reticular
layer
glands
or
fat cells
May
or
may not
be
present
1-Oral
epithelium
4-Submucosa
Basement
membrane
2-basement
membrane

18. Histological structure:
(oral epith. & lamina propria & basement membrane in between &
sub-mucosa )
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1) Oral epithelial: its ectodermal in origin
formed of stratified squamous epith which is
keratinized in some areas & Non-kerarinized in
others.
N.B: stratum = layer

19. Non-keratinized epith.Keratinized epith.
Stratum basaleStratum basale
(basal layer)
Stratum spinosumStratum spinosum (prickle)
(prickle layer)
Intermediate layerStratum granulosum
(granular layer)
Superfacial layerStratum corneum
(keratinized layer)

20. Keratinized Epithelium Nonkeratinized Epithelium
Oral
epithelium

21. 1) Keratinized epithelium: this type found in areas
which subjected to force like gingiva , hard palate
(masticatory mucosa).
N.B: cells which form this layer called keratocytes or
keratinocytes.
*Cells are arranged in 4 layers
(basal & spinous & granular & cornified).
the names of layers derived
from their morphology.

22. Layers of keratinized epith (basal&prickle&granular&cornified).
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1)Basal layer:
1. its single row of columnar or cuboidal cells that is closely attached to
each other & arranged on basement membrane.
2. Cells posses all usual organelles & tonofilaments
(tonofilaments: its fibrous protein synthesis by
ribosomes , seen as long filaments
chemically its cytokeratin ).
3. Its site of cell division since its divided into 2 cells (progenitor cells ,
mturative cells)
*progenitor cells: remain in base to divide again.
*maturative cells : migrate toward the surface.

24. 2) Spinous cell layer:
1. Its consist of several rows of
polyhedral cells of different shapes , size.
2. Spinous layer & basal layer constitute
more than half thickness of the epith.
3. Cells joinded together by
intercellular bridges giving the
cells prickly apperance.
4. Wide inter cellular space compared
with Non-keratinized epith.
5. Its most active cells in protein synthesis.
6. Numerous , well developed organelles.
7. No sudden changes in appearance of cells & there is gradual
decrease in synthetic activity through the layer.
8. In the upper part of this layer there are odland’s bodies .

25. odland’s bodies:
(keratinosomes or membrane coating granules).
• Its present in superfacial layer of
prickle layer or in first layer of
granular layer
• Its may originate from golgi complex.
• This granules discharged in
intercellular space, act as barrier to penetration of
forgein substance.
• Its responsible for thickning of
cell membrane.

26. 3.Granular cell layer:
1. Its several rows of flattened epith. Cells.
2. Many organelles are reduced , cytoplasm will be occupied
by tonofilaments & tonofibrilis.
3. Cells contains large number of small granules called
(keratohyaline granules).
4. Odlands body discharge into inter-cellular space which act
as barrier & increase the thickness of epith.

27. 4.Cornified layer:
1. Its present in keratinized epith as final stage of
maturation.
2. Cell loss all organelles & filled by closely packed
tonofilaments which are surrounded by matrix protein
and this structure called keratin.
3. Its shed (process of desquamation).
4. Weak desmosomes to allaow desquamation.
5. Its provide mechanical , chemical protective function
to the mucosa.

29. 2. Non-keratinized epith.:
(in this type there absence of cornified & granular cell layer).
1. Epith. Is thicker , outer half of epith. Shows changes which distinguished
them from basal , prickle cells.
2. Outer half divided into 2 zones (intermediate , superfacial layer).
3. This cells increase in size and there is accumulation of glycogen , presence
of keratohyaline granules which appear more regular & not associated by
tonofilaments.
4. cells of Outer 2 strata are tightly packed together thus intercellular space
nearly absent.
3. Cells of stratum intermedium contains odlands body with there size ,
shape , location differ from those found in keratinized epith.
3. Super facial layer contains nucleus , few organelles.

32. Thanks
Dr:3mmar