The oral cavity is lined by oral mucosa, which is continuous with the skin and pharyngeal mucosa. The oral mucosa consists of three types - masticatory, lining, and specialized mucosa. Masticatory mucosa covers areas involved in chewing and is keratinized, while lining mucosa covers other soft tissue areas and is non-keratinized. Specialized mucosa covers the dorsal tongue and contains papillae involved in taste. The oral mucosa provides protection, sensation, secretion, permeability and thermal regulation functions.

2. ORAL MUCOSA
The oral cavity is lined with an uninterrupted mucous
membrane, which is continuous with the skin near the
vermilion border of the lips and with the pharyngeal
mucosa in the region of the soft palate and anterior
pillars of fauces.
The epithelium of the oral mucosa originates partly
from the ECTODERM (lips, vestibule, gingiva, cheeks,
palate, floor of the mouth), and pertly from the
endoderm (tongue).

3. MASTICATORY MUCOSA
• free and attached gingiva and hard palate comes in primary contact
with food during mastication and is keratinized.
LINING MUCOSA
• the lips cheeks, vestibule, floor of the mouth, interior surface of the
tongue and soft palate. It does not function in mastication and
therefore has little attrition. It is soft, pliable and non-keratinized.
SPECIALIZED MUCOSA
• on the dorsal surface (dorsum) of the tongue. It is covered with
cornified epithelial papillae

5. Protection
• acts as major barrier to microorganisms
Sensation
• receptors that respond to temperature, touch, pain,
taste; initiates reflexes such as swallowing,
gagging and salivation
Secretion
• saliva, contributes to the maintenance of moist
surface
Permeability and Absorption
• thinnest epithelial regions, floor of the mouth,
more permeable than other areas
Thermal Regulation
• dogs, body heat is dissipated thru the oral mucosa
by panting

7. Two main tissue components:
• stratified squamous
epithelium
Oral
epithelium
• undderlying connective
tissue layer
Lamina Propia
or Corium
The oral mucosa is attached to the underlying structures by
a layer of loose fatty or granular connective tissue containing
major blood vessels and nerves

8. • structureless layer about 1 – 2
micrometers thick; interface
between epithelium and
connective tissue
Basement
Membrane
• irregular and upward
projections of connective tissue
Connective
tissue
papilla
• or rete pegs, epithelial ridges or
pegs that interdigitate with the
connective tissue papilla
Rete
Ridges

13. Orthokeratinization
Keratinization (types) • About 20-30% of the gingiva, the stratum corneumis homogenous and
made up of flat, closely packed keratinized cells without nuclei
Parakeratinization
• Approximately 50-70% of the cases, the stratum corneum is
homogeneous and consists of flat keratinized cells with pyknotic nuclei
and remnants of cytoplasmic organelles
Incomplete Keratinization
• - Least common type, approximately 7-10% of cases and is seen only in
the region of the marginal gingiva. Stratum corneum is homogenous
and consists of 2 cell types, which occasionally form 2 superimposed
layers: the first type of cell is the same as cornified cell of a
parakeratinized stratum corneum; the 2nd type is different from
keratinized cells and seems to reach the stratum corneumand its
surface without being transformed nto a keratinized cell.

14. ORAL EPITHELIUM
Oral epithelium forms the surface of
the oral mucosa that forms a barrier
between the oral environment and
the deeper tissues
It is derived from the embryonic
ectoderm.
It is stratified squamous epithelium
and may or may not be keratinized.
Beneath the epithelium lies the
connective tissue

16. Keratinized oral epithelium
Most of the oral mucosal surface is
lined by nonkeratinized stratified
squamous epithelium except gingiva,
hard palate and dorsal surface of the
tongue where the epithelium is
keratinized
The keratinized cells have no nuclei
and the cytoplasm is displaced by
large numbers of keratin filaments
Keratinized epithelium is associated
with masticatory function and have
four layers of cells

17. Layers of the Keratinized Surface
Epithelium
1.Stratum
Basale
2.Stratum
Spinosum
3.Stratum
Granulosum
4.Stratum
Corneum

18. STRATUM BASALE
The cells of the stratum basale are cuboidal
or low columnar and form a single layer
resting on the basal lamina
The basal lamina is at the interface of the
epithelium and lamina propria
Epithelial cells of the oral mucosa are in a
constant state of renewal
The basal cells show the maximum mitotic
activity

19. STRATUM SPINOSUM
Stratum spinosumis usually several cells
thick
They are shaped like polyhedron with short
cytoplasmic processes
The stratum basale and the first layers of
stratum spinosumare referred to as stratum
germinativum because these cells give rise
to new epithelial cells

20. STRATUM GRANULOSUM
Cells of stratum granulosumare flat and are
found in layers of three to five cells thick
This layer is prominent in keratinized
epithelium (and absent in nonkeratinized
epithelium)
These cells have keratohyaline granules in
their cytoplasm
Keratohyaline granules help to form the
matrix of the keratin fibres found in the
superficial layer

21. STRATUM CORNEUM
Cells of stratum corneum are flat,
devoid of nuclei and full of keratin
filament surrounded by a matrix
These cells are continuously being
sloughed and are replaced by
epithelial cells that migrate from
the underlying layers

22. Nonkeratinized oral
epithelium
Nonkeratinized epithelial cells in the
superfecial layers do not have keratin
filaments in the cytoplasm
The surface cells also have nuclei
The stratum corneum and stratum
granulosumlayers are absent
This epithelium is associated with lining of
the oral cavity

24. Connective tissue
Connective tissue can be differentiated as
Lamina Propria and Submucosa
Lamina propria
• Lamina propria is the connective tissue layer immediately below
the epithelium
Lamina propia can be divided into:
1)papillary layer - prominent in masticatory mucosa
2)reticular layer-prominent in lining mucosa
• Lamina propria consists of blood vessels and cells like
fibroblasts, cells of blood vessels and lymphatics and nerves
• Epithelium is avascular, hence its metabolic needs come via
the vessels of the lamina propria

25. Submucosa
• Submucosa lies below the lamina propria and
serves as an attachment between lamina propria
and bone or skeletal muscle
• It is found in the cheeks, lips and parts of the
palate
• It consists of large blood vessels, nerves and
lymphatics and its functions of mucosa are
nutrition and defensive.

26. Functional types of Oral Mucosa
• Lining mucosa covers all soft
tissues of the oral cavity except the
gingiva, hard palate and the dorsal
surface of the tongue
A) Lining
mucosa
Lip
Lip is covered by lining mucosa
Lip with skin on outer surface
and lining mucosa on inner
surface

27. Vermilion border
The junction between the skin and mucous membrane
is
known as the vermilion border.
Here the epithelium is thin therefore, the red blood
cells in the
capillaries show through contributing to the vermilion
colour

28. Ventral surface of the tongue
The lining mucosa here contains both lamina propria and
submucosa
The submucosa merges with the muscle bundles of the
ventral surface of the tongue

29. Cheek
In the cheek the underlying submucosa contains fat cells and
small mixed salivary glands

30. Floor of the mouth
The mucous membrane of the floor of the mouth is thin and
loosely attached to the underlying structures

31. • Masticatory mucosa covers the gingiva and
hard palate.
• In edentulous mouth, masticatory mucosa
covers the chewing surface of the dental
arches.
B)
Masticatory
mucosa
Gingiva
• Gingiva has keratinized or parakeratinzed epithelium with
no submucosal layer
• It develops from the union of oral epithelium and reduced
enamel epithelium of the developing tooth

32. Hard palate
• The surface of the hard palate that is visible in
the mouth is
covered by masticatory mucosa
• The lateral regions of the posterior part contains
palatine glands
• These glands are purely mucous glands
• The midline of the hard palate is called median
raphe, where there is no submucosa
• A series of folds appear in the anterior part of the
palate
called rugae

36. Mucosa of the Tongue
• Specialized mucosa covers the dorsal surface
of the body of the tongue
• The connective tissue binds the epithelium to
the underlying skeletal muscle
• The epithelium is modified, keratinized,
stratified covered with papillae, which can be
seen by naked eye

37. The different papillae found on the dorsal
surface of the tongue are:
1.Filliform papillae
2.Funginform
papillae
3.Circumvallate
papillae
4.Foliate papillae

41. 1)Filliform papillae
• Filliform papillae are pointed
extensions of the keratinized
epithelial cells
• They are the most numerous papillae
of the tongue
• They are not associated with taste
buds
Scanning electron micrograph
of Filliform papillae
(arrow)

43. 2)Fungiform papillae
• Fungiform papillae are fewer than the filliform
papillae and are
scattered over the dorsal surface of the tongue
• They are rounded elevations above the
surface of the tongue
• They have taste buds on their superior
surfaces
The surface of fungiform papillae is not
keratinized

46. 3)Circumvallate papillae
• The circumvallate papillae are located at the
junction of the
anterior two thirds (body) and posterior one thirds
(base) of
the tongue
• There are eight to twelve in number and are bigger
than
fungiform papillae
• Circumvallate papillae are lined with taste buds and
also
openings of serous glands
• The secretion from the serous glands washes away

48. 4) Foliate papillae
• Foliate papillae are located in the
furrows along the posterior sides of the
tongue
• They may be lined with taste buds
• They are not prominent in human beings