Histology of the Oral Cavity: Mouth

Lips and Cheeks

• The lips are musculofibrous folds that are connected to the gums by superior and inferior frenula.

• The median part of the upper lip shows a shallow external groove, the philtrum.

• The lips consist (from external to internal) chiefly of skin

• The three layers forming the skin can beidentified in all skin sections.

• The epithelium forming the surface layer,the epidermis, is usually the darkest layervisible. Sublayers are visible in theepidermis.

• At the transition from the epidermis to thedermis, staining will become lighter. Thelighter stained layer, the dermis, consistsof dense irregular connective tissue.

• The dermis is much thicker than theepidermis. In thick skin, dermal papillaecreate a very irregular border betweenepidermis and dermis.

• The hypodermis is the lightest layer visibleand consists mainly of adipose tissue.Dense connective tissue strands mayextend from the dermis deep into thehypodermis.

• Tongue• The tongue situated in the floor of

the mouth, is attached by muscles to the hyoid bone, mandible, styloidprocesses, and pharynx.

• The tongue is important in taste, mastication, swallowing, and speech.

• It is composed chiefly of skeletal muscle, is partly covered by mucous membrane, and presents a tip and margin, dorsum, inferior surface, and root

• The tip, or apex, usually rests against the incisors and continues on each side into the margin.

• The oral part of the dorsum may

show a shallow median groove.

• The mucosa has numerous minute lingual papillae:

• (1) the filiform papillae, the narrowest and most numerous; Filiform Papillae

• = plush of tongue

• Parallel rows

• Primary columnar elevation of lamina propria

• 5 – 30 tall secondary papillae

• Epithelium over papillae – end in tapered points

• Hard & scaly (not cornified)

• FILIFORM PAPILLAE OF THE TONGUE

Stained with H&E

• 1 - epithelium covering papilla(stratified squamous keratinizing)

2 - keratinized layer of the epithelium3 - core of the papilla (lamina propria of the mucosa of dorsal surface of the tongue)4 - tongue muscles

Fungiform Papillae

Stained with H&E

1 - epithelium covering papilla

(stratified squamous nonkeratinizing)

2 - core of the papilla (lamina propria

of the mucosa of dorsal surface of the

tongue)

3 - taste buds

(2) Fungiform Papillae

the fungiform papillae, with rounded

heads and containing taste buds

Knob-like

Scattered, single, among filiform papillae

Larger & fewer than filiform papillae

Narrow stalk, rounded top

Size: 1.8 mm. high; 1 mm.

Has 1 to several taste buds

Stained with H&E

1 - epithelium covering papilla(stratified squamous nonkeratinizing)

2 - core of the papilla (lamina propria of the mucosa of dorsal surface of the tongue)3 - taste buds

CIRCUMVALLATE PAPILLAE OF THE TONGUE

much larger than any of others

about 8-12 located in post region of

tongue, just next to sulcus terminalis

have deep furrow’s next to each

papillae = where von Ebner’s glands

open

Von Ebner’s glands = serous lingual

glands

Tooth Structure

• Two main regions – crown and the root

• Crown – exposed part of the tooth above

the gingiva (gum)

• Enamel – acellular, brittle material

composed of calcium salts and

hydroxyapatite crystals is the hardest

substance in the body

– Encapsules the crown of the tooth

• Root – portion of the tooth embedded in

the jawbone

Tooth Structure• Neck – constriction where the crown and

root come together

• Cementum – calcified connective tissue – Covers the root

– Attaches it to the periodontal ligament

• Dentin – bonelike material deep to the enamel cap that forms the bulk of the tooth

• Pulp cavity surrounded by dentin that contains pulp

• Pulp – connective tissue, blood vessels, and nerves

• Root canal – portion of the pulp cavity that extends into the root

• Apical foramen – proximal opening to the root canal

• Odontoblasts – secrete and maintain dentin throughout life

• TOOTH DEVELOPMENT -FORMATION OF DENTAL TISSUES

Stained with H&E

• 1 - ameloblasts (former external cells of the enamel organ)2 - enamel3 - dentine (predentine)4 - odontoblasts (cells which covered the top of dental papilla)5 - dental pulp (former dental papilla)

TOOTH DEVELOPMENT -

FORMATION OF DENTAL TISSUES

Stained with H&E

1 - ameloblasts

2 - enamel

3 - dentine (predentine)

4 - odontoblasts

5 - dental pulp

border between enamel and dentine

is marked with dot line

Salivary Glands• Produce and secrete

saliva that: – Cleanses the mouth

– Moistens and dissolves food chemicals

– Assist in bolus formation

– Contains enzymes that break down starch

• Three pairs of extrinsic glands – parotid, submandibular, and sublingual

• Intrinsic salivary glands (buccal glands) –scattered throughout the oral mucosa

• Parotid – lies anterior to the ear between the masseter muscle and skin

– Parotid duct –opens into the vestibule next to the second upper molar

• Submandibular – lies

along the medial aspect of

the mandibular body

Its ducts open at the

base of the lingual

frenulum.• Sublingual – lies anterior

to the submandibular gland

under the tongue

It opens via 10-12

ducts into the floor of

the mouth.

• PAROTID SALIVARY GLAND

Stained with H&E

• 1 - serous secretory units

(acini)

2 - intercalated excretory

duct

3 - striated excretory duct

4 - interlobular excretory

duct

5 - interlobular connective

tissue septa

PAROTID SALIVARY GLAND

Stained with H&E

1 - serous secretory units

2 - striated excretory duct

3 - interlobular excretory duct

• PAROTID SALIVARY GLAND

Stained with H&E

1 - serous secretory

units

2 - intercalated

excretory duct

3 - striated excretory

duct

PAROTID SALIVARY GLAND

Stained with H&E

1 - serous secretory units

2 - myoepithelial cells

4 - interlobular excretory duct

5 - interlobular connective tissue septa

• PAROTID SALIVARY GLANDinterlobular excretory duct

Stained with H&E

1 - interlobular

excretory duct

2 - interlobular

connective tissue

septa

SUBLINGUAL SALIVARY GLAND

Stained with H&E

1 - lobules of the gland

2 - interlobular connective tissue septa

3 - interlobular excretory duct

• SUBLINGUAL SALIVARY GLAND

Stained with H&E

• 1 - mucous part of mixed secretory unit

2 - serous part of mixed secretory unit

3 - serous secretory unit

4 - mucous secretory unit

5 - intercalated excretory duct

6 - striated excretory duct

7 - interlobular excretory duct

8 - interlobular connective tissue septa

SUBLINGUAL SALIVARY GLAND

Stained with H&E

1 - mucous part of mixed secretory

unit

2 - serous part (serous demilune) of

mixed secretory unit

3 - serous secretory unit

4 - mucous secretory unit

5 - myoepithelial cells

SUBMANDIBULAR SALIVARY

GLAND

Stained with H&E

1 - serous secretory unit

2 - mixed secretory unit

3 - intercalated excretory

duct

4 - striated excretory duct

5 - interlobular excretory

duct

6 - interlobular

connective tissue septa

7 - mucous part of mixed

secretory unit

8 - serous part (serous

demilune) of

mixed secretory unit

• SUBMANDIBULAR

SALIVARY GLAND

Stained with H&E

• 1 - serous secretory unit

2 - mixed secretory unit

3 - intercalated excretory

duct

4 - striated excretory duct

Esophagus• The part of the gastrointestinal tract called

the esophagus is a muscular tube whose

function is to transport foodstuffs from the

mouth to the stomach and to prevent the

retrograde flow of gastric contents.

• Transport is achieved by peristaltic

contractions and relaxation of the

esophageal sphincters (upper and lower),

usually controlled by reflexes and by the

autonomic nervous system.

• In humans the esophagus is covered by

nonkeratinized stratified squamous

epithelium.

• In general, it has the same layers as the

rest of the digestive tract. In the submucosa

are groups of small mucus-secreting

glands, the esophageal glands, whose

secretion facilitates the transport of

foodstuffs and protects the mucosa.

• In the lamina propria of the region

near the stomach are groups of

glands, the esophageal cardiac

glands, that also secrete mucus.

• At the distal end of the esophagus,

the muscular layer consists of only

smooth muscle cells that, close to

the stomach, form the lower

esophageal sphincter; in the mid

portion, a mixture of striated and

smooth muscle cells; and at the

proximal end, only striated muscle

cells.

• Only that portion of the esophagus

that is in the peritoneal cavity is

covered by serosa. The rest is

covered by a layer of connective

tissue, the adventitia, that blends into

the surrounding tissue.

Layers of Esophageal

Wall:

1. Mucosa

2. Submucosa

3. Muscularis

4. Adventitia

5. Striated muscle

6. Striated and smooth

7. Smooth muscle

8. Lamina muscularis

mucosae

9. Esophageal glands

The muscular coat (tunica muscularis)

isble thickness:

an external of longitudinal and an

internal of circular fibers.

The muscular fibers in the upper

part of the esophagus are a red

color, and consist chiefly of the

striped variety; but below they

consist for the most part of

involuntary fibers.

Histological Structure. The esophagus has four coats:

an external or fibrous coata muscular coata submucous or areolar coatand an internal or mucous coat.

Section of the human esophagus. The section is transverse and from near the middle of the gullet.

a. Fibrous covering.

b. Divided fibers of longitudinal muscular coat.c. Transverse muscular fibers.

d. Submucous or areolar layer.e. Muscularis mucosæ.f. Mucous membrane, with vessels and part of a lymphoid nodule.g. Stratified epithelial lining.

h. Mucous gland.i. Gland duct

• The oesophagus has a stratified squamous epithelial lining (SE)which protects the oesophagusfrom trauma;

• the submucosa (SM) secretes mucus from mucous glands (MG).

• The lumen of the oesophagusis surrounded by layers of muscle (M)

• ESOPHAGUSStained with H&E

1 - tunica mucosa

2 - tunica submucosa

3 - tunica muscularis propria

5 - epithelium of the mucosa

6 - lamina propria of the mucosa

9 - glands in the submucosa

• ESOPHAGUSStained with H&E

1 - tunica mucosa

2 - tunica submucosa

3 - tunica muscularis

4- tunica adventitia

5 - epithelium of the mucosa

6 - lamina propria of the mucosa

7 - muscularis mucosae

8 - glands in the lamina propria

• ESOPHAGUS

Stained with H&E

1 - tunica mucosa

2 - tunica submucosa

3 - tunica muscularispropria

4 - tunica adventitia

5 - epithelium of the mucosa

6 - lamina propria of the mucosa

7 - muscularis mucosae

8 - glands in the lamina propria

GASTRO-ESOPHAGEAL

JUNCTION

Stained with H&E

1 – stomach

2 - esophagus

GASTRO-ESOPHAGEAL JUNCTION

Stained with H&E

1 – stomach

2 -esophagus