Oral Cavity and Associated Structures

Junqueira: Chapters 15 & 16TenCate: Chapters 11 & 12Readings in Lab Manual

Lips, Oral cavity (mucosa), Tongue & Salivary glands

DEN 5120C January 29, 2007Dr. Kelly Selman D2-32

Vestibule

Oral Cavityproper

bac

3 Regions of lip:a) Skinb) Red border (or Vermilion zone)c) Mucosa (wet)

Epithelium and underlying CT

Lip

LIP

Minor SalivaryGlands

Mucosa

Hair Follicles

b) Vermillion zone: is the red border of the skin

NOTE: part of it is parakeratinized but not all of it

a) Skin

Muco-cutaneous Junction (wet/dry)

Skin

Hair follicle

Sebaceous gland (holocrine secretion)

Keratinized SSE(Epidermis)

Dermis

SSE-Non-keratinized SSE-Keratinized

BMBM

Surface LayerNK

K

Comparison & Review

Parakeratinized SSE has characteristics of both

TenCate 12-8

Muco-cutaneous junction

Mucosa (wet region)

Deep CT papillae withrich venous supply

Vermillion zone

Cutaneous region (skin)

*SSE keratinized*

VZ

Skin

Mucosa(Non-keratinized SSE)

Para-k

MC Junction

Parakeratinized region of skin

Skin (Keratinized SSE))

Mucocutaneous junction

Mucosa: Wet membrane that opens to the outside

Small intestine

Hard palate and gingiva: masticatory mucosa

Small intestine Cheeks: lining mucosa

TenCate 12-5

•Type CT depends on functional forces exerted on mucosa

•Consists of epithelium and underlying CT•Forms an impenetrable barrier

DCT

Masticatory

Lining

Masticatory:•Hard palate• Gingiva

Lining:•Soft palate•Ventral tongue•Floor of mouth•Cheeks•Lips

Specialized:• Dorsal tongueSpecialized

TenCate 12-1; see Table 12-6

Oral mucosae: Lining, Masticatory & Specialized

Lining mucosa(Lips, cheeks, soft palate, floor of mouth)

Cheek (H&E)SSE

ubmucosa

Nonkeratinized

ucosa

•Flexible mucosa (many elastic fibers), overlies submucosa• Easy to inject into lamina propria (LCT), fluid spreads rapidly but also it is easy for infections to spread

Continuity of Gingival, Sulcular and Junctional epithelium

ep.

Sulcular ep. •The gingival epithelium ispart of a masticatory mucosa

•The Junctional Epitheliumattaches the gingiva to the tooth surface.

•The Junctional Epitheliumis is a circular arrangementof epithelial cells near the base of the gingival sulcus and is attached to both the tooth (enamel) and theunderlying CT

Junctional Epithelium• JE is the principle seal between epithelium and

enamel and is the only barrier between the oral cavity and underlying CT Many lymphocytes.

• Forms during tooth eruption by fusion of the reduced enamel epithelium and overlying oral epithelium.

• This junctional epithelium is different than other epithelia in that it has 2 basal laminae and their composition differs from other basal laminae

• Its intercellular junctions are somewhat different and are rather leaky and thus this epithelium is easily penetrated.

• The connective tissue underlying the JE frequently displays numerous lymphocytes and cells involved in inflammatory reactions.

Circumvallate PapillaFoliate P.

Fungiform P.

Filiform P.Body

Root

Lingual papillae, taste buds, lingual glands, lingual tonsils

Lingual tonsilPalatine tonsil

Sulcus terminalis

Taste & sensation

Tongue (Specialized

mucosa)

Tongue- Large muscular organ in floor of oral cavity- Has striated muscle arranged in 3 planes - Muscle is tightly adhered to mucosa by CT partitions

Dorsal

Foliate papillae

Lateral

Minor Salivary Glands

FP

X-section

Ventral surface of tongue(smooth surface and no papillae)

Lining mucosa

•SSE (nonker.)•LCT

Lamina propria is highly vascularized

Good site for absorption of medicine

Parts of tongue• Body of tongue:

- anterior 2/3 - moveable part - ectodermally derived- contains papillae that

project from its surfacePapillae:

Filiform, fungiform, foliate & circumvallate

• Posterior (Root) of tongue:- endodermally derived- Firmly attached base - pharyngeal part- has lingual tonsils

Filiform papillae(Mucosal projections that give velvety

appearance to tongue)

Functions as abrasive surface. Notaste buds; Keratinized epithelium. ~2 mm long

SEM

Dorsal

Fungiform papillae

SSE

Filiform

TasteBud

Filiform

Fungiform

Taste bud

Dorsal

Fungiform papillae

SEM

Foliate papillae

•Location: form ridges on posterior lateral surface•Functional and noticeable papillae in the neonate that are reduced in size as one ages

Serous glands

Dorsal

TB

ducts

Circumvallate papillae

Serous glands(Von Ebner’s)

CV

CV

Taste

buds

Lingualtonsil

Fungiform

~3 mm

Circumvallate papilla

Wall

Trench

Circumvallate papillae (7-10)

Taste buds

Serous glands(Von Ebner’s)

Dorsal

Serous glands wash substances from taste buds and secrete lipase, which prevents a hydrophobic layer from forming over the taste buds

Circumvallate papillae (H&E)

Taste bud (chemoreceptor)Salt, sweet, sour, bitter

~40 m

Non-keratinized SSE

Taste poreLateral surface of papilla

microvilli

Taste pore Taste pore

Cranial nerves(VII, IX, X)

Taste Buds: intra epithelial sensory organs(mainly found on tongue, soft palate & pharynx)

• TASTE: the ability to respond to dissolved molecules and ions.• There are several different taste sensations: salt, sweet, sour,

bitter (and umami [glutamates]).• Taste buds: aggregations of neuroepithelial (taste receptor) cells.• Each taste bud made of 50-100 taste cells, each representing all

taste sensations.• Each cell has receptors (transmembrane proteins) that bind to

the molecules that give rise to the various taste sensations.• Each cell synapses with a sensory neuron leading to the brain. • Each neuron can connect with more than one taste cell.

Summary Slide of Lingual Papillae

Filiform Fungiform

FoliateCircumvallate

Salivary glands (Major)

Sublingual gland

Submandibulargland

Parotidgland

Saliva• Lubricates oral cavity (750-1200ml/day) and moistens food to assist in

swallowing

• Contains H2O, proteins, electrolytes, glycoproteins, antibodies (IgA)

• Buffers content of oral cavity: high concentration of HCO3 and K+

(prevents demineralization of teeth)

• Initiates digestion of sugars (amylase)

• Contributes to taste (solubilizes food)

• Controls bacterial flora of mouth (lysozyme)

• Defense against pathogens (secretory IgA)

• Source of calcium and phosphate needed for mineralization of newly erupted teeth

Exocrine

Proliferation of epithelial cellsOral epithelium

Ectomesenchyme

Secretory end piece

Endocrine

Review of gland formation

Interlobular duct

Lobule

“Stroma” & “parenchyma” of salivary gland

Lobe

Excretory (lobar) duct

Organization of a Salivary gland

Salivary glands • Gland is partitioned into lobes and lobules

• Organization of secretory cells

acinar or tubular

• Types of secretory and other cells

serous, mucous myoepithelial, duct

•Organization of ducts•Intralobular:

-Intercalated -Striated

•Interlobular-Excretory

Mucous cell

Serous cell

Serous demi-lune

Lumen

*

*

*

*Mixed gland

Relationship of Secretory cell, Myoepithelial cell & Basement membrane

Secretory cell B

A

TenCate 11-19 TenCate 11-20

Myoepithelial cell

Secretory cell

Components of a salivary gland

Striated duct

Serous acinus

Serous demi-lune

Submandibular gland

Mucous cells

Acinus and duct system of salivary gland

• Intercalated ducts and striated ducts are types of intralobular ducts (within lobule)• Excretory ducts are interlobular ducts (drain lobules and found between lobules)

(Intralobular)(Interlobular)

(Intralobular)

Outside of lobuleWithin lobule

HypotonicSaliva

Sodium

Osmolarity

Potassium

Cl-

Striated duct

Na+

K+

Interlobular duct

HCO3

Acinus Intercalated duct

LUMEN

Intercalated ducts (Submandibular gland)

Acinus

Intercalated duct-striatedduct transition

Intercalated duct

SD

BV

Striated ducts (Submandibular gland)

Basal striations

Striated ducts

TenCate Figs. 11-29 &11-31LUMEN LUMEN

BASAL SURFACE BASAL SURFACE

Sublingual gland

Submandibulargland

Parotidgland

Stenson’s duct

Submandibular duct(Wharton’s duct)

Sublingual duct

Salivary glands (Major)

•Largest gland but makes only ~25% of saliva•Secretes into Stenson’s duct•All serous cells•Typically has much adipose tissue •Synthesizes amylase and secretory IgA •Mumps: viral infection (inflammation & pain; facial nerve involved)

Parotid gland

Synthesis of Secretory IgAPrevents adhesion of bacteria and viruses to mucosa of oral cavity (“immunoexclusion”)

Parotid gland

(1)

(2)

(3)(4) (5)

Synthesized by conjoined activity of plasma cells and secretory cells of the parotid gland

Plasma cell

(made by secretory cell)

Secretory IgATranscytosis

of acinus

Parotid gland

Intercalated duct

Striated

Acinus

Plasma cells

Sublingual gland

*Submandibular *Gland (Whartons duct)

Parotidgland

Salivary glands (Major)

Submandibular gland

• Makes >70% saliva • Mixed gland (mainly serous)

• Secretes into Wharton’s duct• Makes lysozyme (hydrolyze bacterial walls)

Intercalated ducts

MC

BV

Sublingual gland

Mucous acini

Mixed acini

Mixed acini

•Smallest gland (makes ~5% saliva)•Mainly mucous secreting•Poorly developed striated ducts

UF

COLLEGE of DENTISTRY