ORAAAL

1. Oral mucosa

2. What is oral mucosa ?
The oral mucosa is the mucous membrane lining the
inside of the mouth and consists of stratified squamous
epithelium termed oral epithelium and an underlying
connective tissue termed lamina propria. The oral cavity
has sometimes been described as a mirror that reflects
the health of the individual.

3. classification of oral mucosa:
Masticatory mucosa:
Location: dorsum of the tongue , hard palate and attached gingiva
Type of the tissue: keratinized stratified squamous epithelium tissue

4. classification of oral mucosa:
Lining mucosa:
Location: found almost everywhere else in the oral cavity, including the:
-Buccal mucosa refers to the inside lining of the cheeks and floor of the
mouth
-Labial mucosa refers to the inside lining of the lips
-Alveolar mucosa refers to the lining between the buccal and labial mucosae.
It is a brighter red, smooth and shiny with many blood vessels

5. classification of oral mucosa:
Specialized mucosa:
Location: specifically in the regions of the taste buds on lingual papillae on the
dorsal surface of the tongue
Types:
 Filiform (keratinized , no taste buds)
 Fungiform (non keratinized , has taste buds)
 Foliate (non keratinized , has taste buds)
 Circumvalate (non keratinized , has many taste buds)

6. STRUCTURE OF ORAL MUCOSA:
Oral mucosa consists of two layers, the surface stratified squamous epithelium and
the deeper lamina propria. In keratinized oral mucosa, the epithelium consists of
four layers:
 Stratum basale (basal layer)
 Stratum spinosum (prickle layer)
 Stratum granulosum (granular layer)
 Stratum corneum (keratinized layer)
In nonkeratinised epithelium, the two deep layers (basale and spinosum) remain
the same but the outer layers are termed the intermediateand superficial layers

8. STRUCTURE OF ORAL MUCOSA:
 Depending on the region of the mouth, the epithelium may be
nonkeratinized or keratinized. Nonkeratinized squamous epithelium covers
the soft palate, inner lips, inner cheeks, and the floor of the mouth, and
ventral surface of the tongue. Keratinized squamous epithelium is present
in the gingiva and hard palate as well as areas of the dorsal surface of the
tongue

9. Functions of oral mucosa
 1-PROTECTION: The oral mucosa separates and protects
deeper tissues and organs.
 2-The sensory function of the oral mucosa is important because it provides
considerable information about events within the oral cavity.
 3-SECRITION : The major secretion associated with the oral mucosa is saliva,

10. Diseases of oral mucosa:
1-Oral cancer (squamous cell carcinoma)
2- Oral Leukoplakia
3-Smoker's palate
4-Oral Candidosis

11. CLINICAL FEATURES OF ORAL MUCOSA:
The oral mucosa is continuous with the skin,
it differs considerably in appearance.
Generally, the oral mucosa is more deeply
colored, most obviously at the lips (where the
bright vermilion border contrasts with the
skin tone).

12. CLINICAL FEATURES OF ORAL MUCOSA:
This coloration represents the combined effect of a number
of factors:
1-The concentration and state of dilation of small blood
vessels in the underlying connective tissue.
2-The thickness of the epithelium, the degree of
keratinization.
3-The amount of melanin pigment in the epithelium.

13. CLINICAL FEATURES OF ORAL MUCOSA:
 Other features that distinguish the oral mucosa from skin
are its moist surface and the absence of appendages. Skin
contains numerous hair follicles, sebaceous glands, and
sweat glands, whereas the oral mucosa essentially only has
minor salivary glands.

14. BOUNDARIES OF THE ORAL MUCOSA:
The oral cavity consists of two parts: an outer
vestibule, bounded by the lips and cheeks,
and the oral cavity proper, separated from
the vestibule by alveolar bone and gingiva.

15. BOUNDARIES OF THE ORAL MUCOSA:
The surface of the oral mucosa tends to be
smoother and have fewer folds or wrinkles
than the skin, but topographic features are
readily apparent on clinical examination.

16. COMPONENT TISSUES AND GLANDS:
The junction between oral epithelium and lamina
propria is obvious, that between the oral mucosa and
underlying tissue, or submucosa, is less easy to
recognize as compared to intestinal mucosa which
clearly is separated from underlying tissues by a layer
of smooth muscle and
elastic fibers..

17. COMPONENT TISSUES AND GLANDS:
The minor salivary glands are situated in the
submucosa of the mucosa. Sebaceous glands are less
frequent than salivary glands; they lie in the lamina
propria and have the same structure as those present
in the skin.

18. COMPONENT TISSUES AND GLANDS:
In several regions of the oral cavity there are
nodules of lymphoid tissue that consist of
crypts formed by invaginations of the
epithelium into the lamina propria.

19. COMPONENT TISSUES AND GLANDS:
The largest accumulations of lymphoid tissue
are found in the posterior part of the oral
cavity, where they form the lingual, palatine,
and pharyngeal tonsils, often known
collectively as Waldeyer’s ring.

20. LANGERHANS CELLS:
Another dendritic cell sometimes seen above the
basal layers of epidermis and oral mucosa is
Langerhans cell. The Langerhans cell is characterized
ultrastructurally by a small rod- or flask-shaped
granule, sometimes called the Birbeck granule.

21. MERKEL CELLS:
The Merkel cell is situated in the basal layer of the
oral epithelium and epidermis. Unlike the melanocyte
and Langerhans cell, the Merkel cell is not dendritic
and does possess keratin tonofilaments and
occasional desmosomes linking it to adjacent cells.

22. JUNCTIONS IN THE ORAL MUCOSA:
Within the oral mucosa are three junctions that merit
further discussion: the mucocutaneous (between the
skin and mucosa), the mucogingival (between the
gingiva and alveolar mucosa), and the dentogingival
(interface between the gingiva and the tooth.

23. DEVELOPMENT OF THE
ORAL MUCOSA:
The primitive oral cavity develops by fusion of the
embryonic stomatodeum with the foregut after
rupture of the buccopharyngeal membrane, at about
26 days of gestation, and thus comes to be lined by
epithelium derived from ectoderm and endoderm.

24. MELANOCYTES AND ORAL PIGMENTATION:
The color of the oral mucosa is the net result of
a number of factors, one of which is
pigmentation. The pigments most commonly
contributing to the color of the oral mucosa are
melanin and hemoglobin. Melanin is produced
by specialized pigment cells, called
melanocytes.

25. MELANOCYTES AND ORAL PIGMENTATION:
Melanin is synthesized within the melanocytes
as small structures
called melanosomes which are transferred into
the cytoplasm of adjacent keratinocytes by the
dendritic processes of melanocytes.