The oral mucosa lines the inside of the mouth and consists of stratified squamous epithelium and underlying connective tissue. It can be classified as masticatory mucosa on the tongue, hard palate and gums; or lining mucosa in other areas like the cheeks and lips. Specialized mucosa contains taste buds. The oral mucosa protects deeper tissues, senses temperature and touch, and secretes saliva for moisture. It has boundaries at the lips, cheeks, hard and soft palates, and floor of the mouth.

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 As a surface lining, the oral mucosa separates and
protects deeper tissues and organs in the oral region from the
environment of the oral cavity. The normal activities of seizing food
and biting and chewing expose the oral soft tissues to mechanical
forces (compression, stretching, and shearing) and surface abrasions
(from hard particles in the diet).

10. FUNCTIONS OF ORAL MUCOSA
• 2-The sensory function of the oral mucosa is important because it
provides considerable information about events within the oral cavity.
In the mouth, receptors respond to temperature,touch and pain..

11. SECRETION:
• The major secretion associated with the oral mucosa is
saliva, produced by the salivary glands, which contributes to
the maintenance of a moist surface. The major salivary
glands are situated distant from the mucosa, and their
secretions pass through the mucosa via long ducts.

12. THERMAL REGULATION:
In some animals (such as the dog) considerable body
heat is dissipated through the oral mucosa by panting
for these animals the mucosa plays a major role in the
regulation of body temperature.

13. 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).

14. 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.

15. 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

16. 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. The hard and soft palates
form the superior zone of the oral cavity proper, and the floor of the
mouth and base of the minor salivary glands.

17. 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.

18. 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..

19. 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.

20. 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.

21. 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.

22. 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 (after the person who first described it under the
electron microscope;

23. 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.

24. 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.

25. 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.