Oral Cavity and Tooth Development Flashcards
the oral cavity is bounded by (superior, inferior, anterior/lateral, posterior)
hard & soft palate superiorly;
tongue & floor of mouth inferiorly;
teeth (dental arcade) anterior & lateral;
oropharynx posterior
vestibule
area enclosed between
lips & teeth
vermillion border
ransitional
zone between external haired skin
& internal oral mucosa
Color derived from
highly vascular
dermis & thin, overlying keratinized
epidermis
what do lips lack (2)
sweat and sebaceous glands
lips are highly sensitive due to
rich sensory innervation
oral cavity is responsible for (3)
ingestion
fragmentation
moistening of food
mastication involves (3)
cutting, chewing and grinding of food by occlusal surfaces of teeth
Assisted by lips, tongue, & salivary glands results in
bolus for swallowing (deglutition)
Oral cavity also involved in (4)
speech
facial expression
sensory perception
respiration
Lining mucosa
non- keratinized mucosa found on inner cheeks, floor of mouth, inferior surface of tongue & soft palate
what does lining mucosa lack?
stratum corner
where is masticatory mucosa present
in areas of high
abrasion
e.g., gingiva (gums)
& hard palate
cell type of masticatory mucosa
Keratinizedor parakeratinized (cells of stratum corneum do not lose nuclei)
specialized mucosa of tongue is restricted to
dorsal surface of the tongue
specialized mucosa is
keratinized
tongue
Muscular organ composed of
interlacing skeletal Mm fibers
tongue is specialized for (2)
manipulation of food and sensation of taste
where are accessory salivary glands scattered throughout the tongue musculature?
within lamina propria and between mm layers
which crania nerves is the tongue innervated by? (5)
- V (general sensation anteriorto sulcus terminalis)
- VII (taste)
- IX (general sensation & taste posteriorto sulcus terminalis)
- X (taste; motor also?)
- XII (motor)
the tongue is supported by
frenulum
frenulum
thin band of connective tissue anchoring tongue to the floor of the mouth
embryologically, anterior 2/3 of the tongue is derived from
ectoderm
posterior 1/3 of the tongue is derived from
pharynx (mesoderm)
what are the anterior and posterior portions of the tongue separated by
groove, sulcus terminalis
both the anterior and posterior surface are covered by
stratified squamous epithelium, keratinized in anterior 2/3
Filiformpapillae
most numerous;
keratinized, short bristles,
distributed in parallel rows
what do filiform papillary lack?
taste buds
filiform papillae are primarily
tactile
fungiform papillae
mushroom-shaped, scattered among filiform
papillae
do funfiform papillae contain taste buds?
yes located on the dorsal surface
foliate papillae
located in furrows/
ridges on lateral portion of tongue
where are taste buds located on foliate papillae
laterally on papillae
what are foliate papillae associated with
salivary glands (von ebners flands( at the base of papilla
— in humans, contain — in children, — with age
rudimentary
taste buds
degenerate
Circumvallate papillae
row of 8-
12 large, dome-shaped papillae
where are circumvallate papillae located?
immediately anterior to sulcus terminals
what are circumvallate papillae surrounded by?
moat like sulcus
circumvallate papillae contain large numbers of
taste buds laterally at about the base
what are circumvallate papillae axxoicated with?
salivary glands (von ebner’s glands) at the base of papilla
In humans, taste buds located on
papillae of tongue (except filliform)
Adults have from 3,000—10,000 taste
buds; past age of 45, many taste buds
—
degenerate
degeneration of taste buds are responsible or
changes in taste with age
taste buds are also scattered over (3)
palate
pharynx
epiglottis
oval taste buds consist of up to 20-30 spindle shaped central
taste cells
taste cells are
gustatory cells
taste cells contain
taste hairs
Taste hairs project from surface of
cell into a central
taste pore
taste hairs are covered by
glycoprotein coat
taste hairs are surrounded by (2)
sustentacular cells
basal cells
Taste cells continuously (2); have lifespan of ~ 10
days in most mammals
lost &
replaced
taste cells associated with
myelinated N endings
which cranial nerve fibers innervate taste cells (3)
VII, IX, & X
Fourbasic tastes:
sweet, sour,
bitter, & salty
Each taste cell contains receptors
for
only one taste
Each taste cell contains receptors
for only one taste, but individual
taste buds contain
a mixture of taste cells
Bitter taste receptors concentrated
on
circumvallate papillae
Fifthtaste recently
discovered, also associated
with circumvallate papillae—
called
umami (savory)
umami detects
ertain AA’s, inc. glutamate, aspartate— characteristic of asparagus, tomatoes, beef, cheese, and MSG
recent evidence of 6th taste for
fat
genetic basis for taste demonstarted through
PTC (phenylthiocarbamide)
tasters=
non tasters=
bitter
nothing
taste may influence
food preferences
hypogeusia
decreased ability to detect taste
type 1 familial dysautonomia
hereditary condition
total absence of taste buds
Underlying mucosa in caudal 1/3 is mass of lymphoid tissue,
lingual tonsil
lingual tonsil is similar to (2) in structure and function
palatine
pharyngeal
Tonsils located in ring ~ nasopharynx; collectively referred to as
Waldeyer’s ring
Waldeyer’s ring functions to protect (2)
respiratory & digestive tract
Uvula
extension of posterior free margin of soft palate
uvula has a central core of
skeletal muscle
uvula is covered by
lignin mucosa
uvula contains large numbers of
submucosal (palatine) glands
uvula prevents food from…
entering the nasal cavity during swallowing
where are salivary glands
distributed throughout submucosa of oral cavity
3 major pairs of salivary glands
parotid
submandibular
sublingual
parotid gland
(largest gland, located on cheeks) almost completely serous
Parotid duct
Stenson’s duct, opens within vestibule, opposite upper 2nd molar
Sublingual
(located below tongue) mostly mucous
Submandibular
(located inferior & medial to ramus of mandible) mixed
Submandibular duct
(= Wharton’s duct), opens at sublingual caruncle
Numerous smaller, — glands scattered throughout oral mucosa
accessory
examples of smaller, accessory glands (5)
lingual, labial, buccal, molar & palatine glands
Compound (branched) tubuloacinar glands—secretory unit is —
acinus
Myoepithelialcells surround
acini
Myoepithelialcells surround acini—contraction aids in
secretion of saliva into ducts
Acini are either (2)
serous or mucous
Serous acini of mixed glands often in form of —
demilunes
Intercalated ducts are lined by
simple cuboidal epithelium
function of intercalated ducts (2)
secrete HCO3, resorb Cl
Larger striated ducts are lined by
simple cuboidal to columnar epithelium
striated ducts contain basal striations, due to
folding of the plasma membrane
function of larger striated ducts (3)
resorb Na
secrete K into saliva
secrete lysozyme and IgA
where do striated ducts empty
large excretory ducts
what are excretory ducts lined by
stratified cuboidal or pseudostratified columnar epithelium
Sympathetic stimulation inhibits aqueous
secretion
Sympathetic stimulation inhibits aqueous secretion, resulting in
thick, viscous saliva, rich in protein (e.g., mucus)
Parasympathetic stimulation leads to
copious, watery saliva
what does saliva contain? (3)
water
glycoproteins
proteins
enzymes such as (2)
amylase
lysozyme
amylase
converts starch to sugar
lysozyme
antibacterial properties
antibodies (2)
IgA inorganic ions (C, P, Cl)
Saliva also high in –, low –, high –
K
Na
bicarbonate (HCO3-)
Average saliva production in humans ~ — ml/ day
600-1500
SKIPPED
functions of saliva (6)
- Moistens oral mucosa & dry food
- Provides carrier medium for sense of taste
- Buffering via high bicarbonate content
- Digestion of carbohydrates via amylase
- Immunologic function—secretion of salivary IgA
- Control of bacterial flora
Control of bacterial flora (3)
- Proteins in saliva cover teeth with acquired pellicle
- Contains Ab’s that prevent tooth decay
- ↓ salivary production exacerbates tooth decay
