E1 Flashcards
(303 cards)
1
Q
Histogeneisis
A
The formation of different tissues from stem cells that are constituents of the primary germ layers
2
Q
Histology
A
The science of the microscopic structures of tissues formed within histogenesis
3
Q
Development
A
The growth of an organ or organism through various formative stages on its way to maturation
4
Q
Growth
A
Increase in weight and spatial dimension that n organ and organism undergoes
5
Q
Formation
A
An organization level involved in the growth and development of an organ and an organism (the way a particular spatial arrangement (shape) of something occurs)
6
Q
Stomadeum
A
A depression between the brain and pericardium in an embryo
7
Q
When does the stomadeum appear in the embryo
A
3rd week
8
Q
What does the stomadeum become
A
It becomes the nasal and oral cavities between weeks 6-8
9
Q
Stomadeum gives rise to ______ which is the precursor of the ______ of the pituitary gland
A
Rathke’s pouch
Anterior lobe
10
Q
The branchial arches and clefts ______ and ______ in the ______ embryonic week
A
Appear
Disappear
4th
11
Q
Arch I becomes
A
Right and left maxillary facial processes
Right and left mandibular facial processes
12
Q
Ectomesenchyme has similar properties
A
To mesenchyme
13
Q
Ectomesenchyme arises from
A
Neural crest cells which arise from the ectoderm germ layers and form in the cranial region
14
Q
Ectomesenchyme plays a major role in the formation of
A
Hard and soft tissues of the head and neck: Bones, muscles, and tooth tissues
15
Q
The place where the upper maxillary and lower mandibular processes meet at either side of the stomadeum becomes
A
Commissura labiorum oris
16
Q
What replaces the cardiac plate as the lower boundary of the stomodeum?
A
The 2 mandibular facial processes
17
Q
The _______ become the posteriorlateral boundaries of the stomodeum
A
2 maxillary facial processes
18
Q
Nasal pits appear within
A
The fontonasal prominence
19
Q
After the appearance of the nasal pits the frontonasal prominence becomes
A
3 prominences
Median nasal facial process
Right and Left Lateral nasal facial process
20
Q
Nasal pits depend to become
A
Nasal ducts
They open into the stomodeum
The ducts become nostrils that open into the nasal cavities
21
Q
Median nasal process becomes
A
Midline of nose
Philtrum of upper lip
22
Q
Right lateral nasal process becomes
A
Lateral sides and ala of nose
Infraorbital part of face
23
Q
Cleft I becomes
A
The external auditory meatus
24
Q
Arch II becomes
A
An embryonic fold of tissue called : Operculum
25
The operculum covers
Arches 3 and 4
Clefts 2 3 4
26
The operculum becomes
Sides of neck below external auditory meatus
27
During 4th week what takes place between facial processes
Merging NOT fusing
28
If merging is not complete by ____ week then clefting occurs
5th week for both maxillary and mandibular prominences
29
Four lingual swellings appear during the 4th week along the
Ventral inside surface of the mandibular process of branchial arch I II and III
30
During the 4th week the buccopharyngeal membrane
Ruptures and the 4 lingual swellings merge to become the tongue
31
_____ becomes posterior third of tongue
Copula
32
______ become anterior 2/3 of tongue
Tuberculin impair and 2 Lateral lingual swelling
33
Primary plate arise from
Inner surface of median nasal facial process
34
Nasal septum arises from
Primary palate
35
Palatine folds arise from
Inner surface of maxillary facial processes
36
Palatine folds move
From a vertical position to a horizontal position above the tongue
37
Palate epithelial fusion begins
In the 6th embryonic week with the epitheal fusion of the primary palate with palatine folds
38
Odontogeneisis begins
In the 6th week
39
Two basic tissues that arise from the ectoderm primary germ layer are involved in tooth development
Epithelium and mesenchyme
40
Dentinogenisis
Formation of dentin
41
Amelogenesis
Formation of enamel
42
Cementogenesis
Formation of cementum
43
Pulpogeneis
Formation of pulp tissue
44
Epithelial stages
Dental lamina stage
Bud Stage
Cap Stage
Bell stage
45
Tooth Germ stages
3 parts of tooth germ
```
Enamel organ (bell) (epithelial)
Dental papilla (mesenchyme)
Dental follicle (mesenchyme)
```
46
Tooth germ stage is
Odonteogenic epithleial and mesenchyme leaves tissues combined: cells of each tissue induced specifically to become formative cells of dentin, enamel, cementum, and pulp tissues
47
Primary Dental Lamina Stage
Two epithelial invaginations appear in the lower anterior region of the lower jaw and later in the same week in the upper jaw
These invagination descend into underlying mesenchyme life tissue and continue posteriorly within the mesenchyme as continuous epithelial bands
48
Facial band
Vestibular lamina
49
Lingual band
Primary dental lamina
50
Vestibular lamina cell death
Will occur in the center of the vestibular lamina leaving a space known as the vestibule
51
Cells arising from the dental lamina become
Odotonogenic epitheal part of the tooth germ
52
Cells at the deep end of the dental lamina where a tooth is destined to develop with develop into
Epithelial buds
53
Each epithelial bud is surrounded by
Mesenchyme
54
Primary buds
Central incisors
Second molars
6-8 weeks
55
Primary Bud: Central incisor
6 weeks in utero
56
Primary Bud: Second Molar
8 Weeks in utero
57
Permanent buds
First molar
Central incisors
Second molar
Third Molar
4 months in utero to 5 years postnatal
58
Permanent Buds: First molar
4 months in utero
59
Permanent Buds: Central Incissors
5 months in utero
60
Permanent Buds: Second mOlar
10 months postnatally
61
Permanent Buds: Third Molar
5 years postnatally
62
A total of ____ epithelial buds arise from the primary dental lamina
16
10 primary
6 permanent molars
63
Each succedaneous tooth has its own
Secondary dental lamina that arises from the lingual side of the primary dental lamina
64
Cap Stage site of enamel knot
Concentration of epithelial cells of cap that is a signaling center: determines if tooth will develop to become an anterior or posterior tooth
65
Epithelial cap undergoes growth and envelops into
A bell shaped epithelial structure called an enamel organ
66
At the bell stage the epithelium is arranged into
4 Distinct cell layers
67
4 Epithelial cells of Enamel Organ
Inner epithelial
Stratum intermedium epithelial
Stellate reticulum
Outer epithleial
68
Secondary dental lamina is _____ to primary tooth germ
Lingual
69
_____ secondary lamina rise in each arch; one for each secondary tooth
10
70
Secondary dental lamina arise from
Primary dental lamina
NOT the oral epithelium
71
Enamel Organ is
Avascaular
72
Enamel Organ: inner epithleial cells
Differentiate into ameloblasts
73
Enamel Organ: after formation of enamel is complete
The ameoloblasts along with the other layers of the enamel organ come together over the surface of the enamel as a protective structure: reduced enamel epithelium
74
Dental Papilla
Is vascular
75
Dental papilla has undifferentiated cells that
Become odontoblasts, fibroblast, reserve cells
Ultimately becomes pulp tissue of tooth
76
Dental follicle is
Vascular
77
Dental follicle has stem cells that become
Cementoblasts, fibroblasts, osteoblasts, and reserve cells
Ultimately becomes periodontal ligament of the periodontum
78
The enamel is attached to both mesenchyme parts of the tooth germ by
A basal lamina
79
Reduced enamel epithelium
The 4 cell layers of enamel organ come together to form a stratified epithelial layer over the enamel surface. It protects the enamel from surrounding connective tissue until the tooth enters the oral cavity
80
Hertwig’s epithelial root sheath
Outer and inner layers come together at the cervical loop forming a double layer
81
Root sheath has 2 main functions
1 Determines root dentin outline
Determines number of root canals of tooth
82
Cervical loop
Site where inner and outer cell layers merge
83
Dentin Stats
50% mineral
| 30% organic matrix
84
Dentin organic matrix
Collagen I
Dentin sialophosphoprotein
85
Odontoblasts differentiate from
Dental papilla cells
86
Odontoblastic process
A long cytoplasmic extension encased in dentin
87
Odontoblastic Layers
Cell free zone
-Nerve and capillary plexus
Cell rich zone
-extensive vascular system
Pulpal core
88
Line of von ebner
Accentuated lines due to disturbances in mineralization.
Oriented in horizontal at approximately right angles to the dentinal tubules which run in the vertical axis
89
More terminal branching of dentinal tubules occurs where
In root dentin compared to coronal dentin
90
Coronal tubules have ____ curvature
S shaped
Curve out then down
Root are straight
91
Pre-dentin
The fibrillation organic matrix before its calcification
92
Primary Dentin
Dentin made during tooth formation
93
Mantle Dentin
Outer layer of primary dentin
94
Secondary Dentin forms by
The slower continuing deposition of dentin by odontoblasts following completion of the root
95
The junction between primary and secondary dentin is characterized by
A change in the direction of dentinal tubules but the tubular structure is continuous with primary dentin
96
Secondary dentin deposition is fastest where?
On the roof and floor of the pulp chamber
97
Tertiary Dentin formation is a local reaction to
Attrition caries or dental restoration
98
The quality of tertiary dentin depends upon
The intensity and duration of the stimulus
99
Tertiary dentin tubules can be
Continuous sparse irregular or absent
100
Reactionary dentin is formed
By preexisting odontoblasts
101
Reparative dentin
Formed by newly differentiated odontoblasts like cells
These cells can be included in the hard tissue which is called osteodentin
102
Sclerotic dentin
Dentin that has become translucent due to calcification of the dentinal tubules as a result of injury or normal aging
More as you age
103
Two patterns of mineralization
Globular
Linear
104
Globular Mineralizatoin
High rates
Irregular fronts
(Mantle layer)
105
Linear Mineralizatoin
Occurs at slower rates where mineralization front appears more uniform
106
Interglobular Dentin
Localized areas of hypomineralixed dentin often just beneath the mantle dentin where globular zones of mineral fail to fuse into a homogenous mass
107
Interglobular dentin is a defect the dentinal tubules pass through but
Peritubular dentin is not present in these areas
108
Peritubular dentin
Surround the dentinal tubules
It is lower in collagen
Higher in Dentin sialophosphjoprotein
More mineralized than intertubular dentin
109
DGI Type I is in people with
Osteogenesis imperfecta
110
In DGI type I the teeth show
Marked discoloration and attrition in both the deciduous and permanent dentition
111
DGI Type I pulpal obliteration
Occurs soon after eruption and sometimes prior to tooth eruption
112
_______ is the most abundant protein in bone skin and other connective tissues
Collagen 1
113
COLIA1 & 2 mutations can
Reduce the amount of collagen
Produce defective collagen molecules
114
2 Collagen type 1 alpha chains fold with one alpha 2 to form
A triple helix
115
COLIA1 mutations cause
Osteogenesis imperfecta
So does A2
116
Glycine changed to
Cysteine
117
DSPP is expressed by
PreOdontoblasts
PreAmeloblasts
Odontoblasts
118
Dentin Sialoprotein is a
Proteoglycan
119
Dentin phosphoprotein is the ____ protein
Most acidic
120
Mutations in DSPP cause
DDII
DGI -II
DGI-III
121
DSPP is cleaved into
DSP and DPP by Extracellular protease
122
Molars of Dspp-/- show
Discoloration and sever attrition leading to complete disappearance of tooth crown
123
1 year DSP (-/-) mice
Enlarged pulp cavity
Decreased mineral density
Globular mineralized zones
124
Dentin Dysplasia
DDI
| DDII
125
Dentinogenesis Imperfecta
DGI-I
DGI-II
DGI-III
126
Dentinogenesis Imperfecta Type II
Is distinct from OI as only the teeth are affected
Caused by mutations in DSPP
Teeth are blue gray or amber brown and opalescent
127
DGI-II on radiographs
Teeth have bulbous crowns, narrow roots, and pulp chambers and root canals that are small or completely obliterated
Enamel may split from dentin when subjected to occlusal stress
128
Dentinogenesis Imperfecta Type III
The teeth appear somewhat variable as in either DGI type I and DGI type II but unlike the latter two traits multiple pulp exposures are observed in the deciduous teeth
Can look normal to pulp obliteration or even shell teeth radiographically
129
Dentin Dysplasia Type I
Clinically both permanent and deciduous teeth are of normal shape form and color in most cases
Radiographically short roots with unusually mobility and early exfoliation
Crescent shaped pulpal remnants parallel to the CEJ in the permanent dentition and total pulpal obliteration in the deciduous dentition
130
Dentin Dysplasia Type II
The deciduous teeth have creatures of DGI Type II
The permanent teeth are of normal shape form and color in most cases
The pulp cavities show a thistle tube deformity and commonly contain pulp stones
Root length is normal
131
DGI II, DGI III and DDII are likely
To be the same disease all cases appear to be caused by dominant negative effects
The effects of DSPP mutation on the protein may determine the severity of the clinical phenotypes
132
23 pairs
Chromosomes (46 total)
133
22 pairs
Autosomes
134
1 pair
Sex chromosomes
135
Gametes hold
1 chromosome from each pair
136
Amelogenesis imperfecta mutation in
AMELX gene on X chromosome
137
Cell differentiation
The process of a generalized cell becoming specialized for a job
138
Induction
The process that initiates differentiation
139
An inducer is
An agent that provides cells with a signal to differentiate
140
A cell must be _______ to receive induction signal
Competent
141
Competence
Ability of cell to receive and respond to a molecular signal
142
Inducer: Bone morphogenic protein
Receptor:_______
Cell surface BMP receptor Type I or II
143
Inducer: Vitamin D
Receptor:_______
Intracellular vitamin D receptor
144
Inducer: Wnt Signal
Receptor:_______
Cell surface LRP6 AND Frizzled receptor
145
Inducing signals comes from outside cell—-> If cell is competent to receive it——>
Intracellular changes——>cell function changes
146
Auto rinse
Self signal
147
Paracrine
Adjacent cells receive signal
148
Endocrine
Distant cells receive signal
149
Signaling affects
Cell differation
Cell proliferation: dividing into more cells
cell migration: moving to a new location
150
Transcription Factors
Proteins that control whether genes will be transcribed into mRNA
151
1 Transcription factor can control expression of
Tens, hundreds of genes
152
Transcription factors can ______target genes
Activate or repress expression of target genes
153
Morula
Ball of cells
Day 3-4
154
Blastocyst
Hollow fluid filled ball
| Day 5
155
Embryoblast
Inner cell mass
ICM forms all tissues of the embryo
(Trohphoblast other cells)
156
Blastocyst on Day 13
Axes established
Bilaminar embryo
2 germ layers
157
2 germ layers
Ectoderm (dorsal)
| Endoderm(ventral)
158
Ectodermal cells converge
Toward the midline to from the primitive streak
159
Ectodermal cells migrate through
The streak between ectoderm and endoderm
160
Gastrulation
Conversion to trilaminar embryo
3rd week
161
Gastrulation
New mesoderm layer separates ectoderm and endoderm
162
Cephalon migrating cells form
Notochord to support embryo
163
Buccopharyngeal membrane remains
Bilateral of ectoderm and endoderm
NO mesoderm
164
Rostro cadaul folding happens during
Week 4
165
Lateral side folding during week
4
166
Cranial neural crest cells have _____ origins
Ectoderm
167
Cranial neural crest cells are adjacent to
Neural tube
168
Neural tube closes at
Day 22
| End of 3rd week
169
Neural crest cells have capacity to ____ & ______
Migrate
Differentiate
170
________ act like mesenchyme to form most of the connective tissues of the head
Ectomesenchyme cells
171
During brain development the ____ expands as_____ _____ &_____
Neural tube
Forebrain
Midbrain
Hindbrain
172
Hindbrain forms
8 rhombomeres
| Bulges
173
Rhombomeres define the
Origins of distinct populations of NCCs
174
NCCs from midbrain and rhombomeres 1 and 2 contribute to
Branchial arch 1
175
Hox TF genes
Ancient Rostral caudal patterning genes that define body segments
176
NCCs that migrate from mid brain and rhombomeres 1 and 2 to the face and first branchial arch are
Hox free
177
All transcription factors include
A DNA binding doain that allows them to interact with genes
178
Homeboy TFs include
180 base pair homeboy with specific sequence
179
Hox TFs Are a subset
Of homeobox genes that are very ancient body patterning directors
180
Pouch
Internal depression
181
Groove/cleft
Separates arches externally
182
Branchial Arch 1
Mandible
Maxilla
Outer and middle ear
183
Treacher Collins Syndrome
Failure of NCC migration to facial region
184
Sequential
Orderly sequence of eve3nts determine whether cells are ready to receive the signal and how they respond
185
Reiterative
Cells use same signaling pathways again and again at different stages
186
Major signal pathways
BMP
FGF
SHH
WNT
187
Reciprocal
EM signals back and forth
188
Stomatodeum day
Day 26
189
Odontogenic epithelium day
27 day
| 4th week
190
Nasal pits bound by LNP MNP day
34 day
| 5th week
191
Dental lamina stage initiating odontogenesis process fusing day
Day 36
| 6th week
192
Fusion complete
Day 38
193
Tooth type determination Field model
Epithelial: signals induce mesenchymal expression of TFs
mesenchymal: TF expression in overlapping domains
194
Tooth type determination Clone theory
Each tooth type derived from a clone of mesenchymal cells programmed by epithelium
When clone of cells reaches a critical mass a tooth bud initiates
Next bud does not initiate until clone moves outside of inhibitory zone
195
Bud stage ___ growth of dental lamina into bud
Down
196
Bud stage _____ growth of mesenchyme packing into condensation
Up
197
Cap stage epithelial growth
Forms concavace cap like structure
198
Cap stage dental papilla =
Condensed ectomesenchyme
199
Cap stage surrounding ectomesenchyme =
Dental follicle
200
Primary enamel knot
Non dividing enamel organ cells in cap stage
Directs proliferation of surrounding epithleial cells
201
Bell stage enamel organ has _____ components
4
202
Bell Stage: Outer enamel epithelium
Cuboidal cells
203
Bell Stage: Inner enamel epithelium
Columnar cells
204
Bell Stage: Stratum intermedium
2-3 cell thick layer adjacent to IEE
205
Bell Stage: Stellate reticulum
Star shaped cells space between hem
206
Late Bell stage: Secondary Enamel Knot
No divine enamel organ cells in bells etage appearing at sites of cups (NOT in incisors )
207
Secondary enamel knots stimulate
Terminal differentiation of odontoblasts to being dentinogeneiss
208
Secondary enamel knots direct proliferation
Of surrounding epithelial cells—-> IEE completes folding determines number and location of cusps
209
Anodontia
Absence of all primary or secondary teeth
210
Oliogodontia
6 or more missing teeth
211
Hypodontia
1-5 missing teeth
212
Hyperdontia
More than the normal numbers of teeth
213
PAX9 mutation
Most affected individuals missing maxillary and mandibular 2nd and 3rd molars
214
The tooth has 4 tissues only one is not connective
Enamel
215
Enamel is _____ derived and formed by specialized _____ cells
```
Ectodermal
Epithelial cells (ameloblast)
```
216
Of the four mineralized tissues enamel is the only one that does not have
An unmineralized or preenamel formation stage
-immature or mature stages
217
First mineralized tissue to appear
Dentin
218
Second mineralized tissue to appear
Enamel
219
Enamel does not contain
Collagen fibers
220
Amelogenin
A seed protein for normal mineralization
221
Enamel proteins are arranged in
A lace like pattern throughout the volume of enamel and closely associated with the surface of the crystals
222
Hydration Shell
Water forming around crystals and proteins in enamel
223
Strae of Retzius
Growth lines of enamel
224
Perikymata
Numerous small transverse ridges on the exposed surfaces of enamel
225
Each perikymata is thought to take aprox ____ days and thus can be used to estimate how long the tooth took to form
8-10 days
226
Perikymata are most noticeable on
Canines
227
Enamel Rods
Structural unit of enamel
228
Hydroxyapatite crystals are most dense in the
Core or center of enamel rods and run parallel to long axis of rod
229
Each enamel rod is formed by
One ameloblast
230
Enamel Sheath
The outer surface of the rod
231
Crystals in the enamel sheath are less dense than those of core and run
In different directions
Higher % of organic substances (Amelin)
232
Interrod substance
Between the sheaths of rods
Crystals are more dense and run at different directions than those of the sheath
233
_______ secreted interrod substance
2 or more ameloblasts secrete the interrod substance
234
Interrod striations
Each enamel rod is built up of segments separated by dark lines that give a striated appearance
235
A rod is segmented because
It’s secreted in a rhythmic manner
236
Enamel Lamella
Lamellae extend for varying depths from the surface of enamel and consist of longitudinally oriented defects filled with enamel protein or organic debris from the organ cavity
237
Enamel Tuft
Tufts project from the dentinoenmale junction for a short distance into enamel and contain greater concentration of enamel protein
238
Enamel Spindle
Spindles extend from the dentin cross the dentinoenamel junction into the enamel for a short distance
239
Hunter-Schreager Bands
Alternating dark and light bands of varying width
Originate at the DEJ border and pass outward ending at some distance from the outer enamel surface
240
Hunter Schreager bands are caused by
Different direction of enamel rods in adjacent layers
241
Change in rod direction minimizes risk of
Cleavage in the axial direction under the influence of masticatory forces. Clinically significant when performing operative dentistry
242
Pulp is _____ but not_______
Vascular but not calcified
243
Functions of pulp
Hydrates dentin
Protective
Defensive
Reparative
244
Pulp origin
Ectoderm-neural crest ectomesnechyme
245
Pulp Functions in development: Inductive
Send BMP to enamel organ
246
Pulp Functions in development: Formative
Odontoblasts secrete organic matrix
Participate in mineralization by transportin ca ions and DSPP
247
Dentin poshophoprotein
Specific to dentin
Binding sites for collagen
Very acidic
248
DSP binds to_______ pulls out _______ and _______ mineralization
Collagen
Ca
Initiation
249
Dentinogenesis begins during what stage
Bell stage
250
What induces odontoblasts differentiation
Enamel organ-inner enamel epithelium
Or 2 enamel knots in molars
251
2 prominent induction molecules
BMP
| WNT
252
DSPP presences is a signe of
Odontoblast differentiation
253
Signaling cascade
Complex many targets for manipulation
254
GSK3
A kinase has inhibitory effect on transcription
255
When WNT bound to receptor, GSK
GSK becomes inactivate
Bcatenin relased travels to nucleus and initiates transcription
256
When there is more WNT signal there is more
Reparative dentin
257
If dentin is bulging into pulp chamber
Tertiary dentin
258
2 ectopic calcifactions of pulp
Pulp stones
| Diffuse calcifactions
259
Pulp stones
Usually in pulp chambers a
260
Diffuse calcifactions
Usually in canals
261
Odontoblast differentiation in the tooth crown
Is induced by signaling molecules secreted by the cells of the enamel organ specifically inner enamel epithelium or enamel knot
262
Odontoblasts secrete dentin before
Any enamel layed down
263
WNT10a can be
Released from pulp cells in adulat pulp after injury
264
Is WNT10a a transcription factor
Not its secreted TF are in cells
265
Odontogenic zone surrounds
Central core
266
Odontogenic zone
Odontoblast layer
Cell free zone
Cell rich zone
267
Cells of the pulp
Odontoblasts
| fibroblast
268
Cells of the pulp: resident
```
Macrophage
T lymphocytes
Eosinophils
Dendritic cells
PMN
```
269
Cells of the pulp: inflammation
B lymphocytes plasma cells masts cells
270
Stem cells in pulp
Source for replacement of odontoblasts or fibroblasts
271
Proteoglycans in the pulp
Are numerous
Allow diffusion
Water retention
272
Glycoproteins in pulp
Fibronectin
Role in cell adhesion of ECM
Holds cells in orderly fashion
273
Collagen of pulp
I and III
provides tensile strength
274
Mature pulp does not contain
DSPP
275
Stem cells have
High capacity for self renewal
| Plastic
276
Stems cells are plastic
Can generate multiple cell types
277
GCSF
Keeps discs in the area
Attract other stem cells from other tissues
Anti apoptosic
278
DPSC
Are multipotent providing raw material for new pulp tissues BUT they have other importation functions:
Anti inflamatory
Secrete tropic factors promoting angiogenesis and neurogenic
279
Junctions between odontoblasts
Desmosoem and adherents junctions-maintain position and polarity
280
Gap junctions
Channel between cells coordinate dentinogenesis s
281
Tight apical weld junctions
Complete to compromise a partial barrier from things diffusion from dentin to pulp
282
Pulp is
Highly vascularized
Has a lymph system
Presence of blood and lympahativ vessels distinguish it from other tooth tissues
283
ADelta Fibers
Sensory pain fibers
284
C fibers
Some are sensory pain fibers
Others are sympathetic
285
Abeta fibers
Sensory pain fibers
286
Innervation begins at
Bell stage
287
Are both primary and secondary dentition innervated
Yes
288
Nerves enter though _______ and terminate in ________
Apical foramen
Pulp dentin border zone and dentin
289
Rashkovs plexus
Plexus of nerves in crown near cell free zone
290
Mechanically activated ion channels
Are embedded in the membranes of nerve fiber endings of Adelt and Abeta fibers in the pulp dentin border region
291
When the nerve fiber endings are deformed
Ion channels open
Sodium flows into the nerve endings
Depolarizing them and giving rise to action potention
292
PIEZO2
Identify of mechanorecepots
A unique class of stretch sensitive ion channels recently identified as underlying touch sensation and proprioception throughout the body
293
Classic odontoblast receptor theory
Out of favors
However the odontoblast most likely has some function in dentinal sensitivity
294
Pain also arise directly
From stimuli in pulp
295
TRP receptors
A family of transmembrane receptors for thermal and inflammatory pain in many regions
296
Dental stimuli—->hydrodynamic forces—>
Abeta ADelta fibers—->shape pain
297
Abeta ADelta location
Dentinal tubules
Superficial pulp
298
Infection or trauma—>Inflammationm—>
C fibers—> dull pain
299
C fibers located
Pulp only
Superficial and deep
300
Sensory(pain) never also have
Inflammatory and immune function
301
Epinephrine added to lidocaine for dental anesthesia would be expected to
Reduce blood flow to pump limit to bleeing
302
Inflammatory meditators cause tooth pain mainly be engaging the hydrodynamic mechanism
False
Acting directly like TRP don’t need hydrodynamic
303
Activation of nerve fibers in dentin and pulp:
Can lead to reals of neuropeptides in the pulp that have pro-inflammatory effects
Can lead to the resale of neuropeptides in the brain that give rise to pain sensations
