Oral Cavity and Tooth Development Flashcards
Oral cavity bounded by _____ superiorly
hard & soft palate
Oral cavity bounded by _____ inferiorly
tongue and floor
Oral cavity bounded by _____ anterior and lateral
teeth (dental arcade)
Oral cavity bounded by _____ posterior
oropharynx
area enclosed between lips & teeth
Vestibule
transitional zone between external haired skin & internal oral mucosa
Vermillion border
Color of oral cavity derived from
highly vascular dermis & thin, overlying keratinized epidermis
____ lack sweat & sebaceous glands•Highly sensitive due to rich sensory innervation
Lips
Oral cavity responsible for ____, _____, and _____ of food
ingestion, fragmentation, & moistening
______ involves cutting, chewing, & grinding of food by occlusal surfaces of teeth; Assisted by lips, tongue, & salivary glands
Mastication
_____ is formed from mastication for swallowing
bolus
______ is also involved in speech, facial expression, sensory perception & respiration
Oral cavity
_____ of oral cavity is composed of non-keratinized mucosa found on inner cheeks, floor of mouth, inferior surface of tongue & soft palate
Lining mucosa
Lining mucosa lacks what layer of epidermis?
Stratum corneum
____ of oral cavity is present in areas of high abrasion, e.g., gingiva (gums) & hard palate; Keratinized or parakeratinized
Masticatory mucosa
_____ of oral cavity is restricted to dorsal surface of tongue; keratinized
Specialized mucosa
____ is a Muscular organ composed of interlacing skeletal Mm fibers; Specialized for manipulation of food and sensation of taste
Tongue
Accessory salivary glands scattered throughout tongue musculature are located within what layers?
lamina propria & between Mm layers
Which cranial nerves innervate the tongue?
V, VII, IX, X, and XII
Which cranial nerve provides general sensation anterior to sulcus terminalis on the tongue?
V
Which cranial nerve provides taste on the tongue?
VII
Which cranial nerve provides general sensation and taste posterior to sulcus terminalis of tongue?
IX
Which cranial nerve provides taste and motor on tongue?
X
Which cranial nerve provides only motor innervation to tongue?
XII
The tongue is supported inferiorly by the ____
frenulum
_____ is a thin band of connective tissue anchoring the tongue to floor of the mouth
lingual frenulum
Embryologically, anterior 2/3 of tongue derived from ____
ectoderm
Embryologically, posterior 1/3 of tongue derived from
pharynx (mesoderm)
Groove that separates the anterior 2/3 and the posterior 1/3
sulcus terminalis
Both the anterior and posterior portion of tongue are covered by ______ epithelium
stratified squamous epithelium
Which portion of the tongue is keratinized?
Anterior 2/3
Which papillae are most numerous; keratinized, short bristles, distributed in parallel rows; Lack taste buds; primarily tactile
Filiform papillae
Which papillae are mushroom-shaped, scattered among filiform papillae; Contain taste buds located on dorsal surface
Fungiform papillae
Which papillae are located in furrows/ ridges on lateral portion of tongue; Taste buds located laterally on papillae; Associated with salivary glands (von Ebner’s glands) at base of papilla; Rudimentary in humans; contain taste buds in children, degenerate with age
Foliate papillae
Ovoid structures in dermal ridges
taste buds
Which papillae are associated with von Ebner’s glands?
Foliate and circumvallate papillae
Which papillae are in a row of 8-12 large, dome-shaped papillae; Located immediately anterior to sulcus terminalis; Surrounded by moat-like sulcus, containing large #’s of taste buds laterally ~ base; Also associated with salivary glands (von Ebner’s glands) at base of papilla
Circumvallate papillae
Where are circumvallate papillae located?
Located immediately anterior to sulcus terminalis
Taste buds on the tongue are located on _____
papillae
Which papillae lack taste buds?
filiform
T/F: Many taste buds degenerate past 45 years of age
True
Taste buds are found on what structures?
Tongue, Palate, pharynx, and epiglottis
Oval taste buds consist of up to 20-30 spindle-shaped central _____
taste cells
Taste cells make up _____
taste buds
Taste cells contain _____
terminal taste hairs
What cells surround taste hairs?
Sustentacular cells and basal cells
What covers taste hairs?
glycoprotein coat
What cranial nerves innervate taste buds?
VII, IX, and X
T/F: Taste cells continuously lost & replaced; have lifespan of ~ 10 days in most mammals
True
T/F: Taste cells associated with myelinated N endings
True
What are the 4 basic tastes?
Sweet, sour, bitter, and salty
Each taste cell contains receptors for how many tastes?
One
T/F: Taste buds contain a mixture of taste cells
True
Bitter taste receptors concentrated on ____ papillae
circumvallate papillae
Taste associated with circumvallate papillae which detects certain AA’s,
umami (savory)
Decreased ability to taste is called
hypogeusia
Is there a genetic basis for taste that influences food preferences?
Yes
Hereditary condition that causes the total absence of taste buds
Type 1 familial dysautonomia
Underlying mucosa of tongue in caudal 1/3 is a mass of ____ tissue
lymphoid tissue
Underlying mucosa of tongue in caudal 1/3 is a mass of lymphoid tissue called ______; similar to palatine and pharyngeal tonsils in structure and function
Lingual tonsil
Which tonsils are located in a ring that are collectively referred to as Waldeyer’s ring?
Lingual, pharyngeal, and palatal tonsils
What are the functions of Waldeyer’s ring?
Protect respiratory and digestive tract
extension of posterior free margin of soft palate; Has central core of skeletal Mm; Covered by lining mucosa, with lg #’s of submucosal (palatine) glands; Prevents food from entering nasal cavity during swallowing
Uvula
What kind of glands are on the uvula?
Submucosal palatine glands
What are the 3 major pairs of salivary glands?
Sublingual, submandibular, and parotid
salivary gland almost completely serous; (largest gland, located on cheeks)
Parotid
opens within vestibule, opposite upper 2nd molar
Parotid duct
salivary gland that is mostly mucous (located below tongue)
Sublingual
salivary gland that is mixed (located inferior & medial to ramus of mandible)
Submandibular
opens at sublingual caruncle
Submandibular duct
Numerous smaller, _______ scattered throughout oral mucosa (lingual, labial, buccal, molar & palatine glands)
accessory glands
The secretory unit of the salivary gland is
Acinus
Salivary glands are composed of ______ glands
compound (branched) tubuloacinar glands
_____ cells surround acini—contraction aids in secretion of saliva into ducts
Myoepithelial cells
Serous acini of mixed glands often in form of
serous demilunes
What are the 2 types of acini?
serous and mucous
_____ are lined by simple cuboidal epithelium (secrete HCO3, resorb Cl)
Intercalated ducts
What kind of epithelium do intercalated ducts possess?
simple cuboidal epithelium
_____Possess basal striations, due to folding of plasma membrane; Function—resorb Na, sec K into saliva; also secrete lysozyme & IgA; Empty into larger excretory ducts
Striated ducts
What kind of epithelium do striated ducts possess?
Simple cuboidal to columnar epithelium
What 2 kinds of epithelium do excretory ducts possess?
stratified cuboidal or pseudostratified columnar epithelium
_____ stimulation inhibits aqueous secretion => thick, viscous saliva, rich in protein
Sympathetic
______ stimulation => copious, watery saliva
Parasympathetic
What 5 things does saliva contain?
water, glycoproteins, proteins, antibodies, and enzymes
____ is an enzyme in saliva that converts starch to sugar
amylase
____ in an enzyme in saliva that is antibacterial
lysozyme
The antibodies in saliva include ___ and ____
IgA and inorganic ions
Is saliva high or low in potassium?
High
Is saliva high or low in sodium?
Low
Is saliva high or low in bicarbonate?
High
What is the average production of saliva in a day for humans?
600-1500 mL per day
____ are proteins in saliva that cover the teeth
acquired pellicle
Function of ____ include 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—•Proteins in saliva cover teeth with acquired pellicle•Contains Ab’s that prevent tooth decay•↓ salivary producKon exacerbates tooth decay
saliva
Functions of _____: Proteins in saliva cover teeth with acquired pellicle•Contains Ab’s that prevent tooth decay•↓ salivary producKon exacerbates tooth decay
bacterial flora
Tooth are grossly divided into what 2 parts?
root and crown
Portion of tooth embedded in bone called
tooth root
tooth root is in a part of the jaw called
alveolar ridge
the tooth socket within the alveolar ridge is called
alveolus
Portion of tooth that projects into oral cavity
crown
Crown is protected by layer of highly mineralized ____, covers crown
enamel
____ is a hard, translucent substance, containing < 1% organic material & 96-98% hydroxyapatite
Enamel
Ectodermal in origin; secreted by tall, columnar ameloblasts of enamel organ
Enamel
Apical, secretory end of ameloblast forms single, large process
Tome’s process
Enamel mineralization is non-uniform, resulting in highly calcified ______—roughly hexagonal, ~4-8μm in diameter
enamel rods or prisms
Enamel rods are Separated by less mineralized _____
interprismatic material
Enamel rods extend from _____ at enamel surface to ______
ameloblasts; dentino-enamel junction
Bulk of tooth composed of less mineralized
dentine
Mesodermal in origin, secreted by odontoblasts of dental papilla Chemically similar to bone, but more mineralized; ~ 70% hydroxyapatite crystals; Also contains Type I collagen & GAG’s
dentin
dentin is secreted by _____
odontoblasts
____ contains odontoblasts that secrete dentin
dental papilla
Dentine arranged in _______—hollow, parallel tubes radiating from pulp cavity
dentine tubules
long, rod-like cytoplasmic processes of odontoblasts
Tome’s fibers
Central pulp cavity contains ____
support structures including sensory Nn & blood vessels
Dentin is innervated by
myelinated nerves
_____ is mesodermal in origin; resembles primitive mesenchyme; Contains stellate fibroblasts, reticular fibers, collagen, & ground substance; Richly supplied by capillaries from arterioles running with periodontal ligament
Dental pulp
Dental pulp contains what types of fibers?
stellate fibroblasts, reticular fibers, collagen, & ground substance
Tooth root is covered by a thin layer of _____ (also mesodermal)—amorphous, collagen-based, calcified tissue~45-50% hydroxyapatite, similar to bone—
cementum
Cementum is manufactured by
cementoblasts
Cementoblasts mature into
cementocytes
Cementum layer anchored to bone of alveolus with fibers of
periodontal ligament
Periodontal ligament is composed of dense, collageous fibers, called _____
Sharpey’s fibers
Run at oblique angle, support tooth in socket; allows slight movement of tooth during mastication
periodontal ligament
occasional clusters of epithelial cells within periodontal ligament
vestigial epithelial rests of Malassez
Region of tooth between root & crown is
neck of tooth
Protected by masticatory oral mucosa called _____ ; covers upper portion of alveolar ridge
gingiva (= gums)
covers upper alveolar bone
attached gingiva
forms cuff or neck of tooth
free gingiva
Space between free gingiva and crown
gingival sulcus
very thin, only 2-3 cells thick, easily breached by bacteria => periodontal disease, gingivitis
crevicular epithelium
Tissues that surround & support tooth collectively referred to as ______ —include epithelium, cementum, periodontal ligament & alveolar bone
periodontium
T/F: Teeth are formed between opposing layers of epithelial cells
True
What 2 layers are teeth formed between?
ameloblasts of enamel organ & odontoblasts of dental papilla
Enamel is of ______ origin
ectodermal
Dentine, cementum, pulp, & periodontal ligament are of _____ origin
mesodermal
6th week of fetal development, a horseshoe-shaped epithelial ridge arises from oral epithelium and Forms ______ in position of future jaws
dental lamina
T/F: In each quadrant, lamina develops several globular, ectodermal swellings (one for each deciduous tooth)
True
Superficial half of epithelial cells of dental lamina forms
enamel organs
Deep half of epithelial cells of dental lamina forms
dental papilla
Enamel organ initially ___-shaped (cap stage)
cup
Cells of enamel organ progressively differentiate, become _______, with extracellular matrix of GAG’s
stellate reticulum
Later forms ____-shaped structure (bellstage)
bell
Cells lining outer, convex surface of enamel organ become
external enamel epithelium
Cells lining concave surface of enamel organ form _______ differentiate into tall, columnar ameloblasts
internal enamel epithelium
enamel formation
Amelogenesis
Deepto developing enamel organs is _____ that develops into dental papilla
primitive mesenchyme;
Cells lining convex surface of dental papilla develop into ____
odontoblasts
Dentin formation
dentinogenesis
T/F: Development of ameloblasts induces differentiation of odontoblasts,
True
T/F: calcification of dentine induces deposition of enamel
True
Tooth formation initiated by deposition of organic _____ by odontoblasts on surface of dental papilla
pre-dentine
Calcificaiton of dentine matrix secondarily induces ____ production
enamel
Odontoblasts have _______, embedded in dentine matrix—form _____
odontoblast processes; dentine tubules
Enamel forms in mineralized columns of _____, separated by less mineralized _____
enamel rods; interprismatic material
Subsequent to deposit of dentine & enamel, dental lamina _____
fragments & atrophies
At time of tooth eruption, enamel organ & ameloblasts _____
degenerate
T/F: Overlying mucosa separates as tooth erupts, exposing crown
True
Dental papilla shrinks, becomes _____, surrounded by dentine
dental pulp
After tooth formation is complete, small amounts of ______ continue to be produced, may eventually obliterate pulp cavity
2’ dentine
Overall shape of ______ determines 3-D shape of tooth crown
enamel organ
Outer rim of enamel organ known as _____ determines cross-sectional outline of tooth
epithelial sheath of Hertwig (= Hertwig’s root sheath)
Surrounding mesenchyme forms ______ => periodontal ligament
dental follicle
Enamel organs of permanent teeth develop as buds from
dental lamina & “deciduous” enamel organ
In case of molars, dental lamina proliferates ____ to form enamel organs of 2’ dentition
caudally
In humans, tooth development begins ____ of fetal development—but tooth eruption does not occur until _____ after birth
~6th week; 6-30 months
______, administered during development of permanent dentition incorporated into enamel => yellow discoloration of teeth
Tetracycline
modified for cutting & biting
Incisors
for puncturing & holding
Canines
generally used for grinding
Premolars & molars
allows lateral & anterior-posterior motion—important for chewing, grinding
TMJ
Raised points on occlusal surfaces of molars & premolars known as
cusps
Flattened posterior surface of lower molars known as
talonid
Premolars and molars can be low crowned, or____ in omnivores
bunodont
Premolars and molars can be very tall, high crowned, _____, as in herbivores
hypsodont
_____ accomplished by osteoblast & osteoclast activity in alveolus
Orthodontia
results when weak acids in food & drink erode calcified enamel, augmented by bacterial action
Dental caries
helps harden enamel & kills bacteria
Fluoride
Caries may extend into dentine or pulp cavity, produce abscesses or death of tooth => ______
root canal
caused by accumulation of calcified food & bacterial debris (plaque) in gingival sulcus => widening of gingival sulcus, possible inflammation & destruction of periodontal ligament
Periodontal disease
Inflammation of gums
gingivitis
Inflammation of periodontal ligament
periodontitis
