the vestibule: space between lips and cheeks, and dental
arches

the oral cavity proper: bounded by teeth, tongue and floor of mouth, palate and fauces

SALIVARY GLANDS DRAIN TO:

parotid glands: largest of the major salivary glands, located in the infratemporal region; drain via parotid ducts (Stenson's)

submandibular glands: located in submandibular triangle of neck; drain via submandibular ducts (Wharton's)

sublingual glands: located in floor of mouth, in sublingual folds; drain via small ducts, or submandibular ducts

minor salivary glands: located in the submucosa throughout the oral cavity; named for location: "buccal", "labial", "lingual", etc.

TONSILS COMMUNICATE WITH:

palatine tonsils..."the tonsils" - located between the palatoglossal and palatopharyngeal folds

tubal tonsils - located in the walls of the nasopharynx, posterior to the opening of hte pharyngotympanic tube

pharyngeal tonsil ("adenoids") - located in the roof of the nasopharynx

lingual tonsil - located on the superior surface of the base of the tongue

oral mucosa typically consists of an epithelium and an underlying lamina propria propria separated by a basal lamina

3 types of oral mucosa

1. Masticatory

Location: covers gingiva and hard palate

Epithelium: Kertainized (lacks stratum lucidum) or parakeratinized (don't lose nucleus, but are pyknotic) stratified squamous epithelium

lamina propria

lamina propria: papillary layer – loose CT, blood vessels, nerves, Meissner’s corpuscles, free nerve endings
reticular layer – dense CT

mucoperiosteum: masticatory mucosa typically connects directly to the periosteum covering the
underlying bone (without an intervening submucosa)

e.g. midline of hard palate ("palatine raphe") & attached gingiva

submucosa (when present in hard palate) contains fat and mucous glands

2. lining mucosa

Location: lips, cheeks, floor of mouth, inferior surface of tongue, soft palate, and alveolar mucosal surfaces; covers muscle, bone, and glands

Epiethelium: non-keratinized, sometimes becomes parakeratinized (vermillion border of lip is keratinized)

4 strata of epithelium: straum basale, spinosum, intermedium, superficiale,

formed of: keratinocytes, Langerhan's cells, melanocytes and Merkel's cells

lamina propria: blood vessels, nerves (both bare nerve endings which extend into the epithelium and
encapsulated endings) and shallow papillae

submucosa: bands of collagen and elastic fibers, which bind mucosa to underlying muscle; minor salivary glands; occasional sebaceous glands: Fordyce spots

3. specialized mucosa

Location: dorsum of tongue, associated with taste

specialized papillae and taste buds

All (filiform, fungiform, circumvallate, foliate) lingual papillae are associated with taste except filiform

filiform:

-smallest and most numerous

-conical, elongated

-CT core, keratinized stratified squamous epithelium

-no taste buds, only mechanical role

cover entire surface of tongue, in rows, pointing backward

fungiform:

-mushroom-shaped

-scattered among filiform papillae, visible to naked eye

-most abundant near tip of tongue

-contain taste buds, stratified squamous epithelium on dorsal surface

circumvallate:

-largest, dome-shaped, 8-12 in number

-located anterior to sulcus terminalis

-each papilla surrounded by "moat" lined with stratified squamous epithelium, and containing numerous taste buds

- ducts of von Ebner's glands (lingual salivary glands) empty into moat, thought to flush out moats

foliate:

-located on parallel ridges separated by deep clefts at right angles to long axis of tongue

-along lateral edge of tongue, harder to identify in elderly people

-contain numerous taste buds

-serous glands empty into clefts

[image]

oval pale-staining bodies which extend the full thickness of the epithelium; open via a taste pore at apex
contain three cell types:

neuroepithelial cells (sensory cells): elongated - extend from basal lamina to taste pore; attached to neighboring cells by gap junctions; synapse at base with afferent sensory neurons (VII, IX, X); turnover time – 10 days
supporting cells: less numerous than sensory cells;
extend from basal lamina to sensory pore; exhibit microvilli, connected by tight junctions; do not synapse with sensory neurons; turnover time – 10 days
basal cells: smaller than other types; located in base of taste bud; act as stem cells for two other cell types

Locations: lingual papillae; palatoglossal arch; soft palate; post. surface of epiglottis; post. wall of pharynx

types of taste: sweet, salty, bitter, sour, umami

tooth structure

crown – portion covered by enamel

clinical crown – part showing above gumline
anatomical crown – entire portion covered by
enamel

root

portion located within alveolus (socket)
outer surface covered by cementum
tooth can have single or multiple roots

tooth tissue

enamel

acellular, cannot be replaced, translucent

laid down in enamel rods, which span the entire thickeness of the enamel

hardest tissue is body - ~96% hydroxyapatite
CONTAINS NO COLLAGEN

secreted by ameloblasts, which derive from
embryonic oral ectoderm
develop from the enamel organ (outgrowth of oral ectoderm, which gives rise to the cells which produce enamel)

dentin

deep to enamel in the crown and cementum in the root, majority of tooth;
contains collagen, 70% mineralized
secreted by odontoblasts, which persist throughout life (mesenchymal in origin)
laid down in dentinal tubules, which contain
odontoblast processes (which extend to/beyond dentinoenamel junction)
yellowish in color

pulpal surface covered by pre-dentin - unmineralized (contain dentin phosphoprotein DPP and dentin sialoprotein DSP)

cementum

covers outer surface of root
attachment for peridontal ligament– Sharpey’s fibers
secreted by cementoblasts
65% mineralized, avascular

most teeth acellular; in molar and pre-molar teeth, apical 1/3 of cementum has cemnetocytes in lacunae

pulp

located in the pulp chamber
richly vascularized and innervated CT
neurovascular structures enter/exit via apical
foramen
odontoblasts are part of pulp

tooth supporting structures

alveolar bone

lines tooth socket
serves as attachment for PDL

periodontal ligament (PDL)

attaches root to alveolar bone

acts as shock absorber

proprioceptive
involved in eruption and remodeling
made of collagen bundles in distinct orientations

gingiva (“gums”)

-is the term given to mucosa covering alveolar bone
-junctional epithelium attaches to the root of the
tooth – prone to inflammation

major salivary glands:  include the parotid, submandibular and sublingual glands
minor salivary glands are primarily
mucous, and are located throughout
the oral mucosa

Structure

1. capsule
major salivary glands covered by CT capsule, with septa dividing gland into lobes and lobules
lymphocytes and plasma cells present in CT; minor glands don't have capsule

2. salivon: a term which refers to a cluster of acini
with associated intercalated, striated and
excretory ducts

acinus: blind-ended sac formed of excretory cells
– either serous, mucous or both; in fixed tissue, serous cells in a mixed acinus form a serous demilune

serous cells

-pyramidal shaped, base sits on basal lamina, apex opens to lumen of acinus
-large amounts of RER, free ribosomes,
-prominent Golgi, abundant secretory (zymogen) granules
-basal and lateral folding, apical junctional
complexes

mucous cells

-mucus stored in mucinogen granules
-cells appear empty in H&E sections
-most organelles located basally, nucleus
somewhat flattened
-mitochondria and Golgi apical
-cells joined by apical junctional complexes

myoepithelial cells

-contractile cells with numerous processes
-found between epithelial cells and basal
lamina, and surround proximal part of duct
system
-difficult to ID in H&E sections

1. intercalated ducts

-originate within acini
-lined by low cuboidal epithelium
-most prominent in serous glands
-possess carbonic anhydrase activity

-secrete bicarbonate ions and absorb chloride ions

2. striated ducts

-lined by simple cuboidal transitioning to
simple columnar
-basal foldings and vertical mitochondria give
striated appearance
-centrally located nuclei
-located intralobularly

-modify saliva:

-reabsorb Na from primary saliva
-secrete K+ and HCO3-
-because more Na+ is resorbed than K+
secreted, secondary saliva is hypotonic

3. excretory ducts

-principal ducts of major salivary glands
-drain into oral cavity
-transition from simple cuboidal to
-pseudostratified columnar or stratified cuboidal, to stratified columnar and sometimes stratified squamous

saliva:

sources

1. salivary glands
2. gingival sulcus
3. tonsillar crypts
4. transudation from epithelial cells

amount: 1200 ml/day

functions:

-wetting of oral mucosa
-moistening of foods for swallowing
-dissolving foods for tasting
-buffering contents of oral cavity
-digestion of carbohydrates – α-amylase
-control of bacteria via lysozyme
-contains IgA