173 terms

Oral histology (cilnical oral histo & Emrbyo)

The first structure in the formation of tooth?
enamel organ
enamel organ for deciduous teeth appear when?

a. 6-8 week old embryo
b. 4 months in utero
c. 10 month old child
a. 6-8 week old embryo (correct)
b. 4 months in utero
c. 10 month old child
the first time enamel organ for permenant teeth appear at what time?
for 1st molar: 4th month in utero - 10 month old child

3rd molar - 5 yrs old child
What embryonic structure divides the <b>mandibular prominence</b> into lip and future alveolar process.
Labial-vestibular lamina

this structure forms a wedge that then breaks down to form the vestibule with only a thin epithelial lining.
What structure burrows into the connective tissue from the lingual aspect of the vestibular lamina?
Dental lamina (arm of epithelial tissue)

There are initially 10 of these arms forming the future 10 deciduous teeth.
The first stage of enamel organ is:
formation of tooth bud by clumping of the the CT cells (Neural crest cells) around the developing dental lamina.
Which stage is formed first?

a. cap stage
b. bell stage
a. cap sate

Cap stage is when the very end of the dental lamina flattens out to form a structure resembling a small flat hat. This formation quickly changes to appear as a bell.
During bell stage, the bell like structure is surrounded by the neural crest cells which are now given the name ________ which will become PDL later.
'Follicle' or 'sac'
The inner enamel epithelium (IEE) is a layer of cuboidal cells that forms the inside rim and whose shape determines what structure?
future DEJ
The group of cells fills the space between the IEE and OEE and act as a bubble wrap protecting the DEJ.
Stellate reticulum
Function of Stratum intermedium?
to pass on metabolites to the future ameloblasts.
What embryonic structure determines the shape of the root of the tooth.
Cervical loop
Once the enamel and dentin are laid down, how does the nutrition gets to IEE and stratum intermedium?
through diffusion of IEE and OEE at a point so the nutritients can be obtained from external vessels.
(T/F) many cysts and tumors arise from the enamel organ.
Amelogenesis and odontogensis processes start at what stage?
<b>late</b> bell stage
(T/F) the change to preameloblast occurs before the formation of preodontoblast but odontoblast produces dentin before ameloblast produces enamel.
Stages of Amelogenesis (4)
1. Morphogenic- inner enamel epithelium
2. Differentiation- polarization of the nuclei
3. Secretory- synthesis of enamel
4. maturation- reduced ameloblast, add'l calcium to 96%
two main proteins involved in amelogenesis:
1. Amelogenin (90% of matrix)
2. Enamelin (10%) - slightly hypomineralized at DEJ and assocaited with <b>enamel tufts</b>
Which enamel protein is associated with Enamel tufts?
mantel dentin is formed using proteins from:
When dentin matrix is first laid down, the odontoblasts use the protein molecules made by nearby connective tissue cells.
ONLY after the initial 150 micron, odontoblasts is able to lay down its own matrix! (T/F)
The dentin is divided into mantel dentin and _____.
The fact that an ameloblast can produce an enamel rod independent of its neighbors depends on which type of junction?
Occluding or tight junction
A channel formed in a gap junction by the attachment of six connexin proteins on one cell to six <b>connexin</b> proteins on another
What percentage of the cellular energy is spent on Na/K pump?
Is Na+ pumped out during phosphorylation or dephosphyrlation of the carrier protein?

K is brought in during dephosphorylation
Attachment plaques consists of dense material of proteins called _________ and _________.
A single ameloblast produces a single rod exuded from ________.
Tome's process
What's the importance of distal terminal web?
to preserve the rod as it is formed by sealing the sides of the ameloblast and preventing any leakage of matrix.
main transmembrane protein in DTW?
Laminin belongs to ________ family.
The collagen IV of basal lamina is formed by:

a. fibroblasts
b. eipthelia
c. neither
b. epithelia
What protein connects the basal lamina to enamel or implant?
Syndecan, a glycoprotein transmembrane molecule.

it also attaches to Type I and III
is a group of <u>glycoproteins</u> found on cell surface and on connective tissue that promote cellular adhesion and migration.
(a complex carbohydrate) binds to fibronectin to <u>enhance</u> the latter's <u>stikyness</u>
What collagen type(s) make(s) up the principal fibers?
Types I and III
______________ extends from <b>basal lamina</b> to the <B>elastic fibers</b> in the CT matrix.
Fibrillin microfibers
Amelogenesis imperfecta is caused by autoimmune reaction to __________.
Pemphigus is caused by deficiency of ________.
Bullous pemphigoid
Bullous separates at Basement membrane

antibodies to bullous pemphigoid antigen on basement membrane

Stable blisters because of normal epithelium (all underneath)

the cause is due to deficiency of transmembrane proteins such as <b>Type XVII collage, laminin, transmembrane integrin</b>.
A mutation in fibrillin microfibers leads to which disorder?
Marfan's syndrome
__________- layer develops keratohyaline granules.
Stratum granulosum
When keratohyaline granules from stratum granulosum have matured to keratin, they form:
Stratum corneum
these are dendritic cells found in the oral mucosa which produce melanin.
(T/F) the term mucosa means epithelium + Lamina propria
the floor of the mouth is an example of:

a. submucosa
b. mucoperiosteum
c. Fibrous submucosa
a. Submucosa (floor of the mouth)
b. Mucoperiostium (attached gingiva)
c. fibrous submucosa (palate)
This term descibes abnormal thickness of the stratum corneum.
This term describes abnormal thickness of the prickle cell layer.
This term describes abnormal mitosis along with hyperchromatism and atypical nuclei in all the layers.
(T/F) intermediate fibers increase in number as the cells approach the surface, esp stratum corneum.
external surface of the plasma membrane with carbohydrates attached to it. they are present in Prickle cell of the lining mucosa.
Elastic fibers are more prominent in MM or LM?
Submucosa layer of MM
non existent (attached directly to underlying bone, mucoperiostium) or a fibrous submucosa that is filled with fat cells (anterior palate) and minor mucous salivary glands (posterior palate) that makes submucosa very rigid yet still able to cushion a load to protect underlyng blood vessels and nevers
Loss of stippling of the attached gingiva along with loss of the free gingival groove is caused by:
edema of the lamina propria and is an early sign of gingivits.
Reduced ameloblast is:

a. cuboidal
b. columnar
a. cuboidal
? -----> reduced ameloblast
2 important functions of reduced enamel epithelium (REE)?
1. protection of enamel
2. forming the initial steps in connecting the oral mucosa to the tooth.
Inner basal lamina
the part of the reduced enamel epithelium which is attached to the enamel by hemidesmosome.

The part that is attached to the surrounding CT by hemidesomoem is called OUTER basal lamina.
(T/F) Junctional Epithelium extends from the CEJ to the part where epithelial tissue is not longer attached to enamel.
Which two layers disappear in masticatory mucosa?
1. Stratum corneum
2. stratum granulosum
Reduced enamel epithelium (REE) is attached only at the cervix (T/F)
focal adhesion
this is the way fibroblasts and other neural crest driven cells migrate from point to point.
__________ fastens the fibroblast to extracellular collagen matrix using a transmembrane macromolecule.
A sticky glycoprotein on the collagen fiber's surface produced by the fibroblast
makes the fibrinonectin more sticky
The transmembrane macromolecule, attaches one end of itself to the sticky combination of <b>fibronectin and perlecan</b> on the collagen fiber while the other end of syndecan along with laminin, connects to the <b>fibroblasts cell's cytoskeleton of intermediate fibers.</b>

Syndecan also connects the underside of the TYPE IV mat to fibroblasts, connective tissue and prosthesis.
Tenasin is secreted by:
(T/F) tooth eruption is due to contraction and relaxation of __________.
Fibroblasts which are attached to collagen which is attached to the tooth <u>cementum</u> by sharpeys fibers.
4th germ layer
neural crests (ectomesenchyme: part connective tissue cells, part epithelial cells)
a type of mesenchyme from the ectoderm, which is influenced by neural crest cells that have migrated to the area.
(T/F) the CT that supports the epithelium determines the type of epithelium.

ex. masticatory and lining epithelium.
As soon as enamel matrix has formed, the cervcial area of the enamel organ forms a sheath of cells, ___________, that will outline the shape of the root to come.
Hertwig's sheat
What structure separates CT cells that lie on the future pulpal area from those that lie on follicle.
Epithelial diaphragm (ED)
<b>Fibroblasts</b> that are next to the outer surface of Hertwig's sheath become ________.
What portion of the anterior teeth roots are covered with Acellular cementum
all of it

2/3 of the posterior teeth
What type of collagen fibers are found in the ACellular cementum matrix?
II and IV

type one in cellular cementum
What type of collagen fibers are found in the PDL?
I and III
Eruption speed
1 mm every 3 months
How does body compensates for occlusal wear?
with deposit of apical cementum
The radicular cysts which are located at the apex are driven from what type of cells?
epithelial cells, to be more specific. from the epithelial cells of the Debris of Malassez that are near the apex of the infected pulp.
The __________ is the transition area between epiphysis and diaphysis.
The first appearance of interredicular dentin appears where?
on the tab of epithelial diaphragm.
Secretion from which cell is mostly composed of protein with some polysaccharide?

a. serous
b. mucous

Therefore you would expect to see a lot of rough ER.
Exocytosis is the process by which __________ cells secrete their products.

a. serous
b. mucous
a. sereous

mucous cells are by rupturing
__________ cells are found around the cell wall of mucous and serous cells and have a contractile ability to squeeze out fluid.
myo-epithelial cells

MC= myoepithelial cells
SC= Serous cell
SEE= Serous secretory end piece
eosinophilic cells, especially in aged, has no known function but tumors can develop.

they are bright red cells that arise from <b>striated ducts</b>.
fat cells replace much of the parenchyma of what glands? What is the consequence of this?
serous glands

Saliva becomes stringy -> loss of the buffering capability of the saliva.
Saliva can pass out of the cell not only at the apex of the cell, the usual exit, but through opening in the sides of the cell into tiny canals called ___________ that lie between cells that also lead into the intercalated ducts.
intercellular canaliculae
What are the three different arrangement of the salivary gland cells?
1. Spherical acinus in <b>serous glands</b>
2. Tubular acinus in <b>mucus glands</b>
3. Tubula acinus (mucous) AND Demilunes of Gianuzii (serous) in mixed acini.
Parotid gland
watery fluid rich in amylase (<b>spherical endpeice</b>)
-- Oncocytes and fat cells take over as age increases
Submandibular gland
mixed gland but mostly serous <b>spherical endpeice</b> plus few demilunes on top of mucous cells.
What two salivary glands have capsules?
parotid and submandibular THUS post-parandial pain is <b>pathognomic</b> symptom of stone blocking the duct at meal times becomes of back pressure of the blocked saliva.
__________ is a mixed gland but mostly mucous.
Sublingual...VERY viscous
-tubular end piece
- many demilunes of Gianuzzi
- No capsule ---> permits early infiltration of malignant tumors.
Most minor salivary glands are _______.
mucous glands
What are the the only two places in the oral cavity where you would not find minro salivary glands?
1. gingiva
2. anterior palate
What are the two MAIN secretory ducts in the oral cavity
1. Inter-cellular canaliculi
2. Apex of parenchymal cells: serous exocytosis...mucous: cell wall rupture
3. Intercalated ducts
4. Striated ducts

5. Psuedostratified ciliated epithelium
6. Stratified squamous: Stenson's and Wharton's ducts
Stenson's duct
parotid duct; route saliva takes from parotid gland into mouth
Wharton's duct
submandibular duct (salivary duct) ~5cm long; much thinner wall than Stenson's duct
Which salivary gland has higher chance of developing malignant tumor formation?
Sublingual (no capsule)
Pain after eating is known as:
Post-prandial pain
What is symtpom that is ONLY assocaited with post-prandial pain?
striated duct
remove Na+ and adds K+ HCO3- in saliva
Mucous cells
demilunes of Gianuzzi are found in abundant in which gland??
sublingual gland
Two structures that prevent <b>lines of cleavage</b> in enamel.
1. Gnarled enamle
2. enamel tufts
__________produces enamel.
(T/f) Enamel is formed from ectoderm but dentin is formed from mesoderm.
the matrix for dentin is deposited by odontoblasts at what rate?
4 micron daily increments.
The extentuated lines of von ebner is called:
lines of owen
What structure(s) give dentin its proper elasticity?
primary and secondary curvature
A fully calcified dentinal tubule is called:
dead tract
change in existing tissue is called:
protective metamorphesis
the dentin that is deposited in response to abrasion caused by tooth brush is:
reparative secondary dentin
We have pulp chamber which is coronal and ___________ which is root canal.
radicular area
most distinctive cells of the pulp.
cells in the greatest numbers in the pulp
What type of collagen is found in the matrix of the pulp?
I and III

others: ground substance (protoglycans and glycoproteins)
What do you find in a young pulp?
lots of fibroblasts with LARGE nuclei and not much collagen.
What causes narrowing of the pulp chamber by age?
deposition of secondary dentin
cementum is ___% calcified
What structure forms the root formation
Hertwig rooth sheath
The tip of the Hertwig sheath is called
cervical loop
___________ eventually forms the epical foramen.
epical diaphragm
Opposite of adult laminar bone is
Immature woven or juvenile bone.
______________ separates stomodeum from GI tract
Buccopharyngeal membrane

It BREAKS DOWN at the END of 4th week.
What two embryonic processes make up the <b>first branchial arch</b>?
Maxillary process + Mandibular process
What structure makes up the <u>second</u> branchial arch?
hyaloid arch
What emrbyonic structure provides the communication between the <b>eye</b> and the <b>nose</b>?
Nasolacrimal Groove

location: lies between the maxillary process (MAX) and Lateral nasal process (LNP)

extends from Inner canthus of the eye to the nose.
5 weeks embryo
Nasal lacrimal groove first appears when?
in 6 weeks embryo
Nasal pit first appears in:
5 weeks embryo
What two structures form the root of the tongue?
2nd and 3rd branchial arch + copula
What structure(s) form the BODY of the tongue?
1. 3rd branchial arch
2. lateral tubercules
3. Tuberculum impar
Fusion of medial nasal process (MNP) and maxillary process takes place in what week?
7th week

If it doesn't happen ----> CLEFT LIP!
Fussion of Medio nasal process with frontal nasal process?
7th week

they form ----> primary palate!!
Future Columella appears in what week?
7th week
In this week, the Lateral tubercules come together pushing the tuberculum impar out of sight.
Week 7
What structure prevents the <b>palatine processes</b> to come together?
the tongue (T)

MC- Meckel's cartilage
MB- Mandibular bone
Tongue finally drops down in ________ week.
9th week
Downgrowth of palatine shelves occur in 9 weeks. (T/F)

palatal plates come together to from the <b>hard</b> palate.

Fuse with the <B>median palatal triangle</b> also occurs in 9 weeks
Fusion of palatal shelves with primary palate occurs in what week?
week 9
What happens if the primary palate does NOT fuse properly with primary palate?
Cleft palate (9 weeks)
What are the three anatomical segments of primary palate?
Median palatal triangle

primary palate is formed from <i>2 medial nasal processes and fronto-nasal processes (MNP and FNP)
The dental lamina and vestibule lamina are formed in what weeks?
5-6 week
Three stages of tooth development:
1. Bud
2. Cap
3. Bell
Star shaped cells, preserve shape, integrity of the future DEJ.
Stellate reticulum
Bell stage starts at _____ weeks
Reduced Enamel epithelium eventually becomes _______.
junctional epithelium
(T/F) Functions of oral mucosa include protection of deeper tissues, sensing temp, and site of glandular activity (saliva.)
A true submucosa is seen in _______.
lining mucosa
This type of mucosa, is NON-keratanized and has superficial and intermediate layers.
Lining mucosa
________ occurs due to mechanical or traumatic <b>irritation</b>. The source are secretion from minor salivary glands into surrounding tissue.
(T/F) mucoceles are not dangerous and therefore removal is not necessarily.

They should completely removed, because they have the tendency to come back.
Langerhan cells
Have immunologic function to recognize and process antigenic material that enters the epithelium and presents it to T lymphocytes.
Langerhans cell histiocytosis
results from disturbances in immunoregulation. The disease manifestations appear as single or multiple radiolucent areas, which may be unrelated to the teeth or may entail destruction of the tooth-supporting bone.
____________ lies between epithelial cell and ct matrix?
lamina Densa
Lamina Lucida is the clear area between Lamina Densa and cell. this layer contains __________.
Transmembrane molecules are proteins of the ____________ family.
Attaching the mat to the extracellular collagen.
__________ is due to loss of TYPE XVII collagen.
Bullous Pemphigoid

entire mucous membrane lifts off from the lamina propria
Radicular cysts are formed from _________.
Debris of Malassez
As eruption begins, the crown of the tooth is covered by a protective single layer of epithelial cells.

its a double layer
What is the source of growth of the condyle when stimulated by hormones due to an adenoma of the anterior lobe of the pituitary gland in acromegaly.
Cartilage growth center is located in:
on the pressure side, the PDL are _________ to the root axis.
Process of destruction of PDL.

They are sequeezed between the root and bone with excessive forces during orthodontic treatment.
Process that must occur in order for the PDL to be restored as the result of hyalinzation.
Undermining resorption
What structures can be seen on the tension side during tooth movement?
-resting line
-wide PDL
-Collagen fibers prependicular to root
Reversal lines
This is in the pressure side
Cementoblast come from:
(T/F) If the pressure of the movement of the tooth is too excessive, the dentin and cementum can also be damaged.
When do each of the following develop?

a. Parotid gland
b. Submandibular gland
c. Sublingual glad
d. Minor salivary gland
a. Parotid gland - 4-6 weeks
b. Submandibular gland - 6 weeks
c. Sublingual glad - 8-12 weeks
d. Minor salivary gland - 8-12 weeks