The oral mucosa lines the inside of the mouth and consists of stratified squamous epithelium and underlying connective tissue. There are three main types of oral mucosa: masticatory mucosa found on the tongue, hard palate and gums which is keratinized; lining mucosa found elsewhere which is non-keratinized; and specialized mucosa on the tongue papillae containing taste buds. The oral mucosa has functions of protection, sensation, secretion and thermal regulation. It differs from skin in its moist appearance and lack of appendages like hair follicles and sebaceous glands.

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. Functions of oral mucosa:
▪ SECRITION : 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.