ما إ�ال لنا لم ع� ال سبحانك قالواالحك�يم العل�يم أنت �نك إ علمتنا

آية ) البقرة (32سورة

بسم الله الرحمن الرحيم

الله صدق

العظيم

2

BYBYDR. Fawzy DarweeshDR. Fawzy Darweesh

Assistant professor of Oral Assistant professor of Oral BiologyBiology

Faculty of DentistryFaculty of DentistryMansoura UniversityMansoura University

Definition: Is the moist lining of the

oral cavity.

At the lips it is continuous with the skin.

At the pharynx it is continuous with the moist mucosa lining the rest of the gut.

ProtectionFunction: Secretion

Sensory Thermal regulation

FunctionsFunctions 1. Protection1. Protection It protects deeper tissues It protects deeper tissues

from mechanical forces, from mechanical forces, surface abrasions, and surface abrasions, and microorganisms.microorganisms.

2. Secretion 2. Secretion Saliva-produced by the salivary Saliva-produced by the salivary

glands which maintains the glands which maintains the surface moist.surface moist.

3. Sensation 3. Sensation By receptors (respond to temp., By receptors (respond to temp.,

touch, thirst, and pain).touch, thirst, and pain). Reflex (swallowing, gagging, and Reflex (swallowing, gagging, and

salivating) are initiated by the salivating) are initiated by the receptors. receptors.

Tongue has taste buds.Tongue has taste buds.

4. Thermal regulation (dog)4. Thermal regulation (dog) Through panting, so Through panting, so

evaporation of water from the evaporation of water from the surface mucosa control the surface mucosa control the animal temperature.animal temperature.

The oral cavity consists of two areas:The oral cavity consists of two areas:

1. 1. An outer vestibule An outer vestibule (bounded by (bounded by the lips and cheeks) .the lips and cheeks) .

2. 2. Oral cavity proper Oral cavity proper (separated (separated from the vestibule by the alveolus from the vestibule by the alveolus bearing the teeth and gingiva) .bearing the teeth and gingiva) .

Three main types of mucosa :Three main types of mucosa :

1. 1. MasticatoryMasticatory e.g. gingiva and hard palate. e.g. gingiva and hard palate. (amounting to (amounting to 25%25% of the total area) of the total area)

2. 2. LiningLining e.g. inferior surface of the tong., e.g. inferior surface of the tong., labial mucosa, buccal mucosa, floor of the labial mucosa, buccal mucosa, floor of the mouth, vestibular fornix, alveolar mucosa, mouth, vestibular fornix, alveolar mucosa, and soft palate. and soft palate.

(amounting to (amounting to 60%60% of the total area) of the total area)

3. 3. SpecializedSpecialized e.g. dorsum of the tongue and e.g. dorsum of the tongue and taste buds.taste buds.

(amounting (amounting 15%15% of the total area). of the total area).

MasticatoryMucosa

SpecializedMucosa

Lining Mucosa = gray shading

ORAL MUCOSAORAL MUCOSAMASTICATORY

LINING

SPECIALIZED

GINGIVA, HARD PALATE DORSUM OF TONGUE

LIPS , CHEEKS, SOFT PALATE,

VENTRAL SURFACE OF TONGUE

ALVEOLAR MUCOSA,

VESTIBULAR FORNIX FLOOR OF

MOUTH

LOOSELY ATTACHED FIRMLY ATTACHED

Component Tissues and General Component Tissues and General Consideration:Consideration:

Two main tissue components: Two main tissue components: I. Oral epithelium (stratified squamous).I. Oral epithelium (stratified squamous).II. Lamina propria (C.T. layer).II. Lamina propria (C.T. layer).

The interface between both is irregular. The interface between both is irregular. (C.T. papillae interdigitate with epith. (C.T. papillae interdigitate with epith.

Rete pegs) (epithelial ridges). Rete pegs) (epithelial ridges).

(Submucosa may or may not be present)

ORAL MUCOSAORAL MUCOSA

Basal cell layer Prickle cell layer Granular cell layerCornified cell layer

basal intermediate superficial

Lamina propriaLamina propriaStratified squamous epithelium

Keratinized Non-keratinized:

•orthoortho-keratin.•parapara-keratin.

Papillarylayer

Reticular layer glands

or fat cells

& B.Vs.+nerves

May or

may not be presen

t

Oral Oral epitheliumepithelium

SubmucosSubmucosaa

Basement

membrane

Main tissue components of the oral mucosa

The interface is termed the The interface is termed the basementbasement membranemembrane..

It contains glycosaminoglycans It contains glycosaminoglycans

(GAG), proteoglycan, and (GAG), proteoglycan, and anchoring fibrils.anchoring fibrils.

EM: basal lamina.EM: basal lamina.

I. Oral Epithelium (st. squ. I. Oral Epithelium (st. squ. epith.)epith.)

It maintains its structural It maintains its structural integrity by continuous cell integrity by continuous cell renewal (mitotic divisions) in renewal (mitotic divisions) in the deepest layers to replace the deepest layers to replace those that are shed.those that are shed.

Thus, the cells consist of :Thus, the cells consist of : 1. A progenitor population (in the basal or 1. A progenitor population (in the basal or

parabasal area and provide new cells).parabasal area and provide new cells). the basal cell layer and 2-3 layers of the the basal cell layer and 2-3 layers of the

spinous cells called stratum germenativum spinous cells called stratum germenativum that capable to produce D.N.A and divides by that capable to produce D.N.A and divides by mitosis to give new cells just sufficient to mitosis to give new cells just sufficient to match those lost by desquamation at the match those lost by desquamation at the surfacesurface

2. A mature population (differentiate to form 2. A mature population (differentiate to form a protective surface layer). a protective surface layer).

Cell divission occurs and each Cell divission occurs and each daughter cell recycles in the daughter cell recycles in the proginator population or enters proginator population or enters the maturing component.the maturing component.

This is known as turnover time.This is known as turnover time.

For example;For example;

1. The turnover time is 41 to 57 1. The turnover time is 41 to 57 days in the gingiva .days in the gingiva . 2. The turnover time is 25 days 2. The turnover time is 25 days in the cheek.in the cheek.

Nonkeratinized buccal epith. Nonkeratinized buccal epith. turns over faster than turns over faster than keratinized gingival epithelium.keratinized gingival epithelium.

Cancer chemotherapeutic drugs Cancer chemotherapeutic drugs act by blocking mitotic division act by blocking mitotic division of rapidly dividing cancer cells, of rapidly dividing cancer cells, as well as normal host cells.as well as normal host cells.

Proliferation

Cell migration

Cell loss

Mitotic figure

Capillary

Connective tissue

B.M.

Stratumbasale

Stratum spinosum

Stratumgranulosum

Stratumcorneum

Laminapropria

Stratified Squamous Stratified Squamous EpitheliumEpithelium

In general, maturation follows In general, maturation follows two main patterns:two main patterns:

1. Keratinization .1. Keratinization . 2. Nonkeratinization.2. Nonkeratinization.

Keratinization Keratinization Masticatory mucosa (hard palate and gingiva).Masticatory mucosa (hard palate and gingiva).

Some region of specialized mucosa (dorsum of Some region of specialized mucosa (dorsum of the tongue).the tongue).

Epithelium is inflexible and tightly bound to Epithelium is inflexible and tightly bound to lamina propria.lamina propria.

The interface between epith. and underlying The interface between epith. and underlying lamina propria shows numerous elongated lamina propria shows numerous elongated papillae.papillae.

Keratinized epith. has 4 layers:Keratinized epith. has 4 layers: 1. The basal layer (stratum basale).1. The basal layer (stratum basale).

2. The prickle cell layer (stratum 2. The prickle cell layer (stratum spinosum).spinosum).

3. The granular layer (stratum 3. The granular layer (stratum granulosum).granulosum).

4. The keratinized layer (stratum corneum).4. The keratinized layer (stratum corneum).

Orthokeratinized oral epithelium

NonkeratinizationNonkeratinization

Lining mucosa. Lining mucosa.

Is thicker than keratinized Is thicker than keratinized epithelium (500 um).epithelium (500 um).

Has smooth interface with C. T. Has smooth interface with C. T.

The layers in nonkeratinized epithelium The layers in nonkeratinized epithelium are:are:

1. Basal layer (stratum basale).1. Basal layer (stratum basale).

2. Intermediate layer (stratum 2. Intermediate layer (stratum intermedium).intermedium).

3. Superficial layer (stratum superficiale).3. Superficial layer (stratum superficiale).

Epithelium

Laminapropria

Submucosa

Keratinized Epithelium Nonkeratinized Epithelium

Oral Oral epitheliuepitheliu

mm

Ultrastructure of the Epithelial CellsUltrastructure of the Epithelial Cells

Cells of Cells of basal layerbasal layer are the least are the least differentiated.differentiated.

They contain: They contain: 1. Cytoplamic organelles.1. Cytoplamic organelles.2. Desmosomes. 2. Desmosomes. 3. Tonofilaments (synthesized by 3. Tonofilaments (synthesized by

ribosomes).ribosomes).

Tonofilaments represent Tonofilaments represent intracellular proteins known intracellular proteins known as as cytokeratinscytokeratins (characteristic (characteristic constituents of epithelial constituents of epithelial cells).cells).

So, these epith. cells are So, these epith. cells are called called keratinocyteskeratinocytes. .

1- Thickening of the adjacent cell membrane.

2- A pair of attachment plaque.

3- Tonofilaments. 4- An intervening extracellular structure.

The desmosomes

Intercellular Junction

DesmosomeTight junction

Gap junction

Adhesion between the epith. Adhesion between the epith. cells and C.T. is by cells and C.T. is by hemidesmosomeshemidesmosomes..

Ultrastructure of basal lamina (EM) Hemidesmosomes (arrowheads)

Junction between epith. and C.T.

Two other types of connection: Two other types of connection: 1. Gap junction. 1. Gap junction. 2. Tight junction.2. Tight junction.

The next layer : The next layer : prickel cell layerprickel cell layer and and granular layergranular layer in keratinized in keratinized and and intermediate layerintermediate layer in in nonkeratinized epith.nonkeratinized epith.

InIn both, granules discharge both, granules discharge their contents into the their contents into the intercellular spaces, and intercellular spaces, and

Thickening of intracellular Thickening of intracellular (inner) membrane of the (inner) membrane of the superficial cells.superficial cells.

In keratinized epith.In keratinized epith., as the , as the cells of granular layer reach cells of granular layer reach the junction with keratinized the junction with keratinized layer, a sudden changes occur.layer, a sudden changes occur.

These changes are: These changes are: 1. All the organelles with the nuclei and 1. All the organelles with the nuclei and

keratohyaline granules disappear.keratohyaline granules disappear.2. The cells dehydrated. 2. The cells dehydrated. 3. The keratinized layer become packed 3. The keratinized layer become packed

with filaments, flattened, assume the with filaments, flattened, assume the form of hexagonal disks (squames) .form of hexagonal disks (squames) .

This pattern of maturation is termed This pattern of maturation is termed ortho-keratinizationortho-keratinization..

For masticatory mucosa, For masticatory mucosa, parakeratinizationparakeratinization may occur: may occur:

1. Incomplete removal of organelles 1. Incomplete removal of organelles from the cells of granular layer. from the cells of granular layer.

2. The nuclei remain shrunken or 2. The nuclei remain shrunken or pyknotic. pyknotic.

3. Remnants of other organelles 3. Remnants of other organelles may present in the squames.may present in the squames.

Types of KeratinizationTypes of Keratinization orthokeratinized or

parakeratinized

In nonkeratinized epith.:In nonkeratinized epith.:1. Increase in cell size (intermediate layer).1. Increase in cell size (intermediate layer).2. In the superficial cell layer : 2. In the superficial cell layer :

The cells appear more flattenend.The cells appear more flattenend. Accumulation of glycogen. Accumulation of glycogen. The cells contain dispersed tonofilament. The cells contain dispersed tonofilament. The nuclei and some keratohyaline gr. The nuclei and some keratohyaline gr.

remain. remain. Diminished no. of other cell organelles. Diminished no. of other cell organelles. No signs of keratinization. No signs of keratinization.

Histological Histological structurestructure:: Stratified

Squamousepitheliumepithelium

EpitheliumEpithelium

Papillarylayer

Reticular layer

Lamina propriaLamina propria(C.T.)(C.T.)

SubmucosSubmucosaa

Nonkeratinocytes in the oral Nonkeratinocytes in the oral epithelium : (Not participate in the epithelium : (Not participate in the process of maturation) process of maturation)

1. Melanocytes. 1. Melanocytes. 2. Langerhan's cells. 2. Langerhan's cells. 3. Markel’s cells. 3. Markel’s cells. 4. Inflammatory cells (lymphocytes).4. Inflammatory cells (lymphocytes). ( ( They form 10% of the epith. cellsThey form 10% of the epith. cells

))

Characteristics of Nonkeratinocytes in Oral Characteristics of Nonkeratinocytes in Oral Epithelium Epithelium

Cell TypeLevel in Epithelium

OriginFunction

MelanocyteBasal & sometimesparabasal

Neural crest cellsMelanin synthesis and transfer to surrounding keratinocytes

Langerhan's cell PredominantlySuprabasal

Bone marrowAntigen trapping and processing

Markel’s cell Basal Epithelial cells Tactile sensory cell

LymphocyteVariable Blood Associtated with inflammatory response in oral mucosa

All these cells, All these cells, except Merkel except Merkel cellscells, lack desmosomal , lack desmosomal attachment to adjacent cells so attachment to adjacent cells so that during histologic that during histologic processing the cytoplasm processing the cytoplasm shrinks around the nucleus to shrinks around the nucleus to produce the produce the clear haloclear halo. .

NonkeratinocytesClear cells

Langerhan’s cells

MelanocytesMerkle cells

Blood cells

1 -Pigment cell )Melanocyte, blast)

2 -Langerhan’s cell3 -Merkel’s cell

Shape

Small body with long slender and branched process present in the I.C.S of epith. contain melanin granules

(melanosomes)

Similar in shape.Contain granules )langerhan’s granules(

(Bir-beck granules)

They do not have

long processes.Contain small membrane bounded granules

LocationBasal and parabasal layers

High level cell and may be found at lower levels.

Basally in epithelium

Stain by H&E

Not stained so called (Clear dentritic cell)

Not stained so called (Clear dentritic cell)

Not stained so called

(Clear but not dentritic cell)

Special stain

DOPA reaction ) for tyrosinase enzyme(

Gold chloridePAS +ve

Nonkeratinocytes in oral Nonkeratinocytes in oral epitheliumepithelium

These cells have the following criteria:These cells have the following criteria:1- 1- Present in both keratinized and non-Present in both keratinized and non-

kertinized epithelium.kertinized epithelium.2- 2- Appear as clear cells by ordinary H&E Appear as clear cells by ordinary H&E

stain, they stain, they need special stains.need special stains.3- 3- Present as scattered cells and not in Present as scattered cells and not in

sheetssheets..4- 4- A clear hallows around their nuclei.A clear hallows around their nuclei.5- 5- Their cytoplasm is free from Their cytoplasm is free from

tonofilaments (except Merkel’s cells). tonofilaments (except Merkel’s cells). 6- 6- No cellular junctions.No cellular junctions.7- 7- They do not play any role in synthesis They do not play any role in synthesis

of of keratohyaline granules or keratin.keratohyaline granules or keratin.

Junction of the Epth. and lamina propriaJunction of the Epth. and lamina propria Light microscope: Basement Light microscope: Basement

membrane. (structureless band membrane. (structureless band in H & E)in H & E)

EM: Basal lamina. EM: Basal lamina. (lamina lucida and lamina densa + (lamina lucida and lamina densa +

anchoring fibers) anchoring fibers)

All the basal lamina, except its All the basal lamina, except its anchoring fibrils, is anchoring fibrils, is synthesized by the epithelium.synthesized by the epithelium.

II. Lamina PropriaII. Lamina Propria Can be devided into 2 layers:Can be devided into 2 layers:

1. The superficial papillary layer. 1. The superficial papillary layer. 2. The deeper reticular layer.2. The deeper reticular layer.

The lamina propria consists of :The lamina propria consists of :1.1. Cells Cells • Synthetic cells (fibroblasts, fat cells)Synthetic cells (fibroblasts, fat cells)• (UMC).(UMC).• Inflammatory cells (lymphocytes, plama Inflammatory cells (lymphocytes, plama

cells, macrophages, monocytes, mast cells, macrophages, monocytes, mast cells, and neutrophils).cells, and neutrophils).

2. Blood vessels. 2. Blood vessels. 3. Nerves.3. Nerves.5. Fibers (collagen and elastic) embedded in 5. Fibers (collagen and elastic) embedded in

ground substance (ground substance (proteoglycous proteoglycous andand glycoproteins)glycoproteins)..

The papillary zone may be absent in The papillary zone may be absent in some areas (alveolar some areas (alveolar mucosa). mucosa).

The reticular zone is always present. The reticular zone is always present.

The lamina propria may attach to The lamina propria may attach to periosteum or it may overlay the periosteum or it may overlay the submucosa. submucosa.

SubmucosaSubmucosa Consists of C.T. of varying thickness and Consists of C.T. of varying thickness and

density.density. Attaches the MM to the underlying Attaches the MM to the underlying

structures (loose or firm).structures (loose or firm).

Thus the MM may be movable or Thus the MM may be movable or immovable.immovable.

May be present or absentMay be present or absent . .

It contains: It contains: 1. Glands. 1. Glands. 2. Blood vessels. 2. Blood vessels. 3. Nerves. 3. Nerves. 4. Adipose tissue.4. Adipose tissue.

Masticatory MucosaMasticatory Mucosa The epith. is moderately thick The epith. is moderately thick

and may be orthokeratinized or and may be orthokeratinized or parakeratinized . parakeratinized .

B.M. is convoluted (numerous B.M. is convoluted (numerous elongated papillae).elongated papillae).

The lamina propria is thick. The lamina propria is thick.

It covers immobile structures It covers immobile structures (e.g. palate and alveolar (e.g. palate and alveolar process).process).

Bound firmly to the periosteum.Bound firmly to the periosteum.

Hard PalateHard Palate MM is immovable.MM is immovable. Pink in color.Pink in color.

The lamina propria is The lamina propria is thicker thicker anteriorly anteriorly and has numerous and has numerous long papillae.long papillae.

GingivaGingiva

Hard palate

SPECIALIZED

Masticatory mucosa covering the palate

Dense submucosa attatching m. m. to periosteum

Various regions can be Various regions can be distinguished because of distinguished because of varying structures of the varying structures of the submucous layer.submucous layer.

These regions are:These regions are:1. Gingival region (adjacent to the 1. Gingival region (adjacent to the

teeth).teeth).2. palatine raphe (extending from 2. palatine raphe (extending from

incisive papilla posteriorly). incisive papilla posteriorly). 3. Anterolateral area (fatty 3. Anterolateral area (fatty

zone)between the raphe and gingiva. zone)between the raphe and gingiva. 4. Posterolateral area (glandular zone) 4. Posterolateral area (glandular zone)

between the raphe and gingiva.between the raphe and gingiva.

Hard Palate Macro-anatomyincisi

ve papill

amedian palatine raphe

soft palate

uvula

palatine gingiva

palatine rugae

antero-lateral (fatty zone)postero-

lateral (glandular

zone)

Palate : dense lamina propria with fat in some regions of the submucosa

Histology of Hard Histology of Hard PalatePalate

Submucosa

Fatty zone

Glandular zone

Epithelial rete pegs are regular, tall and numerous

Mucosa

The peripheral zones (The peripheral zones (palatine palatine gingivagingiva) do not have a ) do not have a submucosa (identical with the submucosa (identical with the gingiva and the palatine gingiva and the palatine raphe).raphe).

GingivaGingiva Surrounds the neck of the teeth Surrounds the neck of the teeth

and extends to the alveolar and extends to the alveolar mucosa. mucosa.

It is made up of It is made up of st. squ. epith. st. squ. epith. which may be orthokeratinized which may be orthokeratinized (15%) , nonkeratinized (10%) , or (15%) , nonkeratinized (10%) , or parakeratinized (75%).parakeratinized (75%).

Histology of Histology of GingivaGingiva

Stratified squamous keratenized epithelium

Lamina propria

Epithelial rete pegC.T. papilla

TallNumerousSlenderIrregular

No submucosa

The gingiva is limited on the The gingiva is limited on the outer surface by the outer surface by the mucogingival junction mucogingival junction which which separates it from the alveolar separates it from the alveolar mucosa. mucosa.

Mucogingival junction

Gingiva

Alveolar mucosa

Labial mucosa

Alveolar mucosa

Interdentalpapilla

Free ging. grooveAttached gingivaFree gingiva

Mucogengival junction(keratinized gingiva – right ; nonkeratinized mucosa – left)

On the inner surface of the On the inner surface of the lower jaw a line of demarcation lower jaw a line of demarcation is found between the gingiva is found between the gingiva and the mucosa on the floor of and the mucosa on the floor of the mouth.the mouth.

On the palate the distinction On the palate the distinction between the gingiva and the between the gingiva and the peripheral palatal mucosa is not peripheral palatal mucosa is not so sharp.so sharp.

The gingival is divided into :The gingival is divided into :1. The free gingiva.1. The free gingiva.2. The attached gingiva. 2. The attached gingiva. 3.The interdental papilla.3.The interdental papilla.

Enamel

Free Gingiva

Free GingivalGroove

AttachedGingiva

Attached gingiva with thick layer of keratin (no distinct submucosa)

Free gingival groove: between Free gingival groove: between the free gingiva and the the free gingiva and the attached gingival (0.5 attached gingival (0.5 –– 1.5 mm 1.5 mm at or apical to the botton of the at or apical to the botton of the nonkeratinized gingival sulcus).nonkeratinized gingival sulcus).

The gingival surface appears The gingival surface appears stippledstippled (due to epith. ridges and numerous (due to epith. ridges and numerous collagen bundles attaching the tissue collagen bundles attaching the tissue to periosteum).to periosteum).

The gingiva appears depressed The gingiva appears depressed between adjacent teeth (between the between adjacent teeth (between the eminence of the socket) and form eminence of the socket) and form slight vertical folds called slight vertical folds called interdental interdental groovesgrooves..

InterdentalpapillaFree gingivalgroove

Interdental foldsin interdental groove

Mucogingivaljunction

Alveolarmucosa

Free gingiva

Attachedgingiva(stippled)

Gingivalmargin

Gingival marginFree gingiva

attached gingiva

Gingivalsulcus

Gingival stippling

Free gingival groove

Dentin

Space ofenamelSulcular epithelium

Junctional epithelium

cementum

dentinogingiva

l fibers

Gingiva – Micro-Anatomy

The interdental papillaThe interdental papilla Triangular when viewed from the Triangular when viewed from the

vestibular aspect. vestibular aspect. In a 3 dimensional view, it is In a 3 dimensional view, it is

pyramidalpyramidal between the ant. teeth and between the ant. teeth and tenttent shaped between post. teeth. shaped between post. teeth.

The central part is concave (below the The central part is concave (below the contact eara) and is called the contact eara) and is called the gingival gingival colcol which is covered by thin which is covered by thin nonkeratinizednonkeratinized epithepith..

Gingiva – Macro-Anatomy

Free gingiva

attached gingiva

Gingival stipplingFree

gingival groove

palepink

“ col region”

Interdental papilla and Interdental papilla and gingival Colgingival Col

Gingival col( non-

keratenized)

Contact point

Col

Gingival ligaments Gingival ligaments 1. Dentogingival group .1. Dentogingival group .2. Alveologingival group. 2. Alveologingival group. 3. Circular group. 3. Circular group. 4. Dentoperiosteal group. 4. Dentoperiosteal group. 5. Transseptal group 5. Transseptal group

(interdental lig.).(interdental lig.).

Gingival LigamentGingival Ligament

Alveolog. gr.

Dentog. gr.

Dentoperios. gr.

Circular gr.

Melanin pigment is present in the gingival Melanin pigment is present in the gingival epith.epith.

Elaborated by melanocytes (basal layer).Elaborated by melanocytes (basal layer).

Can be studied by dopa reaction or silver Can be studied by dopa reaction or silver staining techniques.staining techniques.

The number of melanocytes is constant (no The number of melanocytes is constant (no

difference in their no. in blacks or whites).difference in their no. in blacks or whites).

Pigmented gingiva

Attached gingiva

Melanin pigment

Gingival SulcusGingival Sulcus Extends from the free gingival Extends from the free gingival

margin to the dentogingival margin to the dentogingival junction. junction.

The sulcular epith. is The sulcular epith. is nonkeratinizednonkeratinized..

It lacks epith. ridges.It lacks epith. ridges.

Gingival marginFree gingiva

attached gingiva

Gingivalsulcus

Gingival stippling

Free gingival groove

Dentin

Space ofenamelSulcular epithelium

Junctional epithelium

cementum

dentinogingiva

l fibers

Gingiva – Micro-Anatomy

The sulcular epith. is The sulcular epith. is continuous with the gingival continuous with the gingival epith. and the attachment epith. epith. and the attachment epith.

They have a continouous basal They have a continouous basal lamina.lamina.

• Nonkeratinized stratified squamous epith.• Thinner than epith. of gingiva.• Lacks epithelial ridges i.e. has smooth interface with lamina propria.• Continuous with gingival epith. & attachement epith.• All three epithelia have a continuous basal lamina

Gingival SulcusGingival Sulcus

Lining MucosaLining Mucosa The epith. is The epith. is thickerthicker than that of than that of

masticatory mucosa.masticatory mucosa. The epith. is The epith. is nonkeratinizednonkeratinized..

The surface is The surface is flexibleflexible (withstand (withstand streaching).streaching).

The interface with C.T. is The interface with C.T. is smoothsmooth..

The lamina propria is The lamina propria is thickerthicker than in masticatory mucosa.than in masticatory mucosa.

It contains fewer irregular It contains fewer irregular

collagen fibers.collagen fibers. It contains It contains elastic fibers elastic fibers

(control the extensibility).(control the extensibility).

Where lining mucosa covers Where lining mucosa covers musclemuscle (lip, cheeks, underside (lip, cheeks, underside of the tongue), the mucosa is of the tongue), the mucosa is fixed to fascia by collagen and fixed to fascia by collagen and elastic fibers.elastic fibers.

Different zones of lining mucosa Different zones of lining mucosa vary from one another in the vary from one another in the structure of their submucosa.structure of their submucosa.

The alveolar and vestibular The alveolar and vestibular mucosa and mucosa covering mucosa and mucosa covering the floor of the mouth are the floor of the mouth are attached looselyattached loosely to the to the underlying structure by a underlying structure by a thickthick submucosasubmucosa..

By contrast, mucosa of the lips, By contrast, mucosa of the lips, cheeks, and underside of the cheeks, and underside of the tongue is tongue is bound firmlybound firmly to the to the underlying muscle.underlying muscle.

Submucosa isSubmucosa is thin thin..

Different zones of the Different zones of the submucosa contain minor submucosa contain minor salivary glandssalivary glands, and, and

Sometimes Sometimes sebaceous glandssebaceous glands

(labial and buccal mucosa).(labial and buccal mucosa).

Sebaceous glands in the mucosa of the cheekAppear as yellowish spots(Fordyce’s granules)

Sebaceousglands

Salivary glands

Alveolar mucosa

Floor of the mouth

Vestibular fornix

Loosely Attached “Movable”mucosa

loosely attached to periosteum

loosly attached to underlying structures

allows mobility of the tongue

allows mobility of lips and cheeks

Alveolar mucosa

mucogingival junction

Epithelium: st. sq. nonker. epith ,.few or no epith. ridges

lamina propria:

Loose C.T, collagen & elastic fibersSubmucosa: thick elastic fibers

& mixed salivary glands

Floor of the mouth Very thin epith.lamina propria

highly vascularizedVestibular

fornix

Loosely Attached“Movable”mucosa

Firmly Attached Immovable Firmly Attached Immovable mucosamucosa Lip & cheek

mucosaInferior surfaceof the tongue

Soft palate

Oral side

Nasal side:pseudustratified

ciliated epith .

Specializd MucosaSpecializd Mucosa Location: dorsal surface of the tongue.Location: dorsal surface of the tongue. Covered by masticatory mucosa Covered by masticatory mucosa

(keratinized).(keratinized).

Containing different types of ling. Containing different types of ling. papillae. papillae.

Some of these papillae bear taste buds.Some of these papillae bear taste buds.

(kerat. and nonkerat).

(nonkerat).

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Microanatomy of the tongueMicroanatomy of the tongue::

Specialized mucosaSpecialized mucosa: : ) )Dorsal surface of the tongueDorsal surface of the tongue.).)

The dorsal surface of the The dorsal surface of the tongue is divided intotongue is divided into::Anterior 2/3 or papillary or Anterior 2/3 or papillary or movable partmovable part..Posterior 1/3 or root or base Posterior 1/3 or root or base of the tongue (lymphatic)of the tongue (lymphatic)..These two parts are separated by These two parts are separated by

V V shapeshape sulcus terminalssulcus terminals..

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Anterior 2/3 or oral Anterior 2/3 or oral part or papillary part or papillary

partpart::Covered by tongue Covered by tongue

papillae taste budspapillae taste buds..

Microanatomy of the tongueMicroanatomy of the tongue::

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Tongue papillaTongue papilla : :

((11)) Filliform papillaFilliform papilla::ConeCone shaped shaped..High conical High conical

structure arranged structure arranged in parallel rows and in parallel rows and

near the post 1/3 near the post 1/3 the raw became the raw became

parallel toparallel to V V shape shape sulcus terminalssulcus terminals..

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•It is covered by Stratified Squamous It is covered by Stratified Squamous Keratinized EpitheliumKeratinized Epithelium

•It has a C.T core (primary papilla) that It has a C.T core (primary papilla) that

may send from 1-2 secondary papillamay send from 1-2 secondary papilla..

•It does It does notnot contain contain taste budstaste buds..

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((22 ) )Fungiform papillae: (fungus Fungiform papillae: (fungus like)like)

MushroomMushroom like narrow like narrow at the base with smooth at the base with smooth

rounded toprounded top..Present on the dorsal Present on the dorsal surface of the Tongue surface of the Tongue between the Filliform between the Filliform

papillapapilla..Are numerous at the tip Are numerous at the tip

of the tongueof the tongue..Covered by ST.SQ. Non Covered by ST.SQ. Non

K. EPK. EP..

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Fungiform papillaeFungiform papillaePrimary C.T papillae 1-3 Primary C.T papillae 1-3 secondary C.T papillae secondary C.T papillae make the B.V. near its make the B.V. near its

surface so it appears redsurface so it appears red..It contains 1-2 taste It contains 1-2 taste

budsbuds..The papilla at the tongue The papilla at the tongue tiptip is responsible for the is responsible for the sweetsweet sensation and that sensation and that of the of the laterallateral borders is borders is

responsible for responsible for saltsalt sensationsensation . .

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((33 ) )circumvalate papillacircumvalate papilla::

From 4-12 in numberFrom 4-12 in number..present anterior to present anterior to

sulcus Terminalissulcus Terminalis..They not protrude They not protrude above the tongue above the tongue

surfacesurface..It is surrounded by It is surrounded by

deep troughdeep trough..the wall of the trough the wall of the trough

contains taste budscontains taste buds..Von EbnerVon Ebner minor minor

salivary glands open in salivary glands open in the bottomthe bottom . .

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Von Ebner glandsVon Ebner glands

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Circumvalate papillaCircumvalate papilla

The trough cleans food The trough cleans food debris and help taste debris and help taste

sensationsensation..It has narrow base and It has narrow base and

wide surface with wide surface with central core of C.T central core of C.T

which send secondary which send secondary C.T papilla to the ST.SQ. C.T papilla to the ST.SQ.

Non K. EPNon K. EP..It is responsible for It is responsible for

bitterbitter sensation sensation..

((44 ) )Foliate papilla: (leaf like)Foliate papilla: (leaf like)..

Present as sharp Present as sharp parallel clefts on the parallel clefts on the lateral side of sulcus lateral side of sulcus

TerminalisTerminalis..It surrounded by It surrounded by

through in which Von through in which Von Ebner minor Salivary Ebner minor Salivary

glands openglands open..It contains taste budsIt contains taste buds..

It responsible for It responsible for SourSour sensationsensation..

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Taste budsTaste buds::

SiteSite::All tongue papilla except All tongue papilla except

Filliform papillaFilliform papilla..Soft palateSoft palate..

Posterior surface of Posterior surface of epiglottisepiglottis . .ShapeShape::

ovoid with roundedovoid with rounded Base toward C.T and Base toward C.T and

pointedpointed At the outer surface At the outer surface

(taste pore)(taste pore)..SizeSize::

8080 M height x 40 M widthM height x 40 M width..

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HistologyHistology-:-:Outer supporting cellsOuter supporting cells

typetype: cells like layers of : cells like layers of onion and are in onion and are in contact with the contact with the epithelium they are rod epithelium they are rod shape with basal shape with basal nucleusnucleus..Inner supporting cellsInner supporting cells type:type: rod shape cells rod shape cells with basal nucleuswith basal nucleus . .

Neuro- epithelial cells Neuro- epithelial cells (receptors of taste (receptors of taste stimuli) they are 10-12 stimuli) they are 10-12 and present between and present between the inner supporting the inner supporting cellscells..

Taste Bud

3 -Neuroepithelial cell

1 -Outer supporting cell

2 -Inner supporting cell

Taste pore

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Taste budsTaste buds

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They are They are slender with with basally basally dark dark

stainedstained nucleusnucleus, ,

and apically and apically stiff bristlestiff bristle

like process like process extended to extended to

the space the space beneath the beneath the

taste poretaste pore..

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Nerve plexus Nerve plexus present beneath present beneath

taste bud in the C.T taste bud in the C.T same nerve fibers same nerve fibers

enter it and end in enter it and end in contact with the contact with the

taste cellstaste cells . .

Taste SensationTaste Sensation1. Any substance to be tasted must 1. Any substance to be tasted must

become dissolved in saliva and become dissolved in saliva and passed to the taste pores. passed to the taste pores.

2. This affects the microvilli of the 2. This affects the microvilli of the taste cells (hairlets).taste cells (hairlets).

3. So, a nerve impulse is set up 3. So, a nerve impulse is set up and transmitted along the and transmitted along the sensory nerve fibers to the brain.sensory nerve fibers to the brain.

SweetSweet is tasted at the tip (fungiform). is tasted at the tip (fungiform).

SaltySalty at the lateral border of papillary at the lateral border of papillary portion (fungiform).portion (fungiform).

BitterBitter (circumvallate-midde area). (circumvallate-midde area). SourSour (foliate-lateral area) on the (foliate-lateral area) on the

posterior part of the tongue.posterior part of the tongue. (bitter is also tasted on the palate).(bitter is also tasted on the palate).

Taste distributionSweet & salt: FungiformSour: Foliat

Bitter: Vallate (palate)

Sweet and salty taste Sweet and salty taste sensations are mediated by sensations are mediated by chordatympani.chordatympani.

Bitter and sour taste Bitter and sour taste sensations are mediated by sensations are mediated by glossopharyngeal nerve.glossopharyngeal nerve.

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Lingual tonsilsLingual tonsils : :

It is small rounded or oval It is small rounded or oval elevations composed of elevations composed of

lymphatic nodules in the under lymphatic nodules in the under lying C.T known as lingual lying C.T known as lingual

follicle is covered by ST.SQ. follicle is covered by ST.SQ. Non K. EP. That extends darn in Non K. EP. That extends darn in many sites to form lingual cryptmany sites to form lingual crypt..The lymphatic tissue composed The lymphatic tissue composed

of germinal centers and diffused of germinal centers and diffused lymphatic tissue fill the spaces lymphatic tissue fill the spaces

between these centersbetween these centers..Into the bottom of these lingual Into the bottom of these lingual

crypt duct from the crypt duct from the WeberWeber minor salivary glands openedminor salivary glands opened..

Lingual cryptLymphatic nodules)follicles)

Weber salivary glands

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Inferior surface of the tongueInferior surface of the tongue

•Firmly attached lining mucosaFirmly attached lining mucosa . .

•Non keratinized epitheliumNon keratinized epithelium..

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Muscles of the TongueMuscles of the Tongue

Two groups of tongue:Two groups of tongue: muscles the muscles the intrinsicintrinsic

and and extrinsicextrinsic are united are united into one organ ,however, into one organ ,however,

has separate structural has separate structural and functional and functional characteristicscharacteristics

11--ExtrinsicExtrinsicGenioglossus MuscleGenioglossus MuscleHyoglossus MuscleHyoglossus MuscleStyloglossus MuscleStyloglossus Muscle

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Muscle of the tongueMuscle of the tongue

22--IntrinsticIntrinsticlongitudinal fiberslongitudinal fiberstransverse fiberstransverse fibersvertical fibersvertical fibers

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Innervations of the tongueInnervations of the tongue : :

Anterior 2/3Anterior 2/3:: Chorda Tympani for taste Chorda Tympani for taste

sensationsensation.. Lingual nerve for general Lingual nerve for general

sensationsensation..Posterior 1/3Posterior 1/3::

Glosspharyngeal nerve for taste Glosspharyngeal nerve for taste and general sensationand general sensation..

The hypoglossal nerve for The hypoglossal nerve for motor supplymotor supply..

(keratinized(No taste buds)

Circumvallate papilla with deep groove into which openthe duct of minor salivary glands

Keratinized epith.: superiorlyNonkeratinized epith.: laterallyContains taste buds laterally

Seen more frequently in mammals other than human beings