DIGESTIVE SYSTEM

ORAL CAVITYOral cavity consists of the mouth and its structures, which include the tongue, teeth and their supporting structures (periodontium), major and minor salivary glands, and tonsils.

Divided into vestibule and oral cavity proper.

MUCOSA

• A mucous tissue lining various tubular structures consisting of epithelium, lamina propria, and, in the digestive tract, a layer of smooth muscle (muscularis mucosae).

MUCOSA OF ORAL CAVITY

Masticatory mucosa• Has a keratinized

and parakeratinized stratified squamous epithelium

• Found in gums and hard palate

Lining mucosa• Non keratinized

epithelium• Few papillae• Found on lips,

cheeks,floor of oral cavity

Specialized mucosa• Associated with

taste sensation• Restricted to

dorsal surface of tongue

LIPSCutaneous area

Red area

Oral mucosa

CHEEKSSkin with sebaceous and sweat glandsMucosa lined by Stratified squamous non cornified epitheliumLamina propria is compact, contain papilla and connected by a submucosa to the underlying skeletal muscle.Submucosa has elastic fibers and tubuloalveolar glands

GUMSEpithelium

Lamina propria

No submucosa and no glands

HARD PALATEEpithelium keratinized

Long vascular papillae

Periosteum of the hard palate

Submucosa with collagen fibers and gland

SOFT PALATEOral surface

Pharyngeal surfaceMucosaSubmucosaGlands Skeletal muscles

TONGUEThe main bulk of the tongue, particularly of the anterior two-thirds, is skeletal muscle.

The interlacing muscle fibers course chiefly in three directions, longitudinally, transversely, and vertically, an arrangement which gives maximal mobility and physical control.

LOWER SURFACEStratified squamous noncornified epithelium

Lamina propria is thin and closely bound to underlying muscle.

DORSAL SURFACEAnterior 2/3: Lingual papillae

Posterior 1/3: Mucosal ridges and lingual tonsils

No submucosa

FILIFORM PAPILLAEMost numerousSmallestEvenly distributedSlender core of vascular epitheliumStratified squamous epitheliumSecondary projections

FUNGIFORM PAPILLAE

Few in numberInterspersed among the filiform papillaeRounded summits and broader basesNoncornified epitheliumHighly vascular connective tissue

1.STRATIFIED SQUAMOUS NONCORNIFIED EPITHELIUM2.LAMINA PROPRIA3.TASTE BUD

FOLIATE PAPILLAEAlong the posterolateral border of the tongue there are folds of the mucous membrane, sometimes called the foliate papillae.

Not well developed in humans.

In some animals,e.g.,rabbits, it constitute the principle site of aggregation of taste buds.

CIRCUMVALLATE PAPILLAE

9-12 in numberResemble fungiform papillaeMuch largerSurrounded by a trench and a wallSmall oval bodies, taste buds

TASTE BUDS

TASTE SENSES

DORSAL SURFACE OF THE POSTERIOR THIRD OF THE

TONGUEFree of papillae

Has mucosal ridges and lingual tonsils

ANATOMICAL DIVISION

Crown

Root

Neck

COMPONENTS OF TOOTH

Enamel

Dentin

Cementum

Pulp

ENAMEL• Consists ofEnamel rodsInter rod enamel• Secreted by

ameloblasts• At apical pole------

Tomes process• At the base---------

cluster of mitochondria

ENAMELAcellular mineralized tissue that covers the crown of toothHardest substance in the bodyOnce formed, can't be replaced96-98% exist mainly

as hydroxyapatite crystals

DENTIN• Calcified tissue

harder than bone• Dentin is produced

by neural crest derived odontoblasts of the adjacent mesenchyme

• Sensitive structure

PERIODONTIUM

• Cementum• Alveolar bone proper• Periodontal ligament• Gingiva

PULPA C.T. compartment bounded by the tooth dentin

Apical foramen

Vascular & neural networks

Cavity decreases with age

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