Test 1 Flashcards
(124 cards)
1
Q
Diff b/t formation, growth, development
A
F: organization and spatial arrangement
G: increase in weight and shape
D: maturation
2
Q
Crown-rump measurement at 3rd embryonic week and at 8th week (start of fetal stage)
A
3mm
30mm
3
Q
3 parts of the stomodeum at 3rd emb. Week
A
Frontal prom. (Sup.)
Cardiac plate (inf)
Buccopharyngeal membrane
4
Q
Rathke’s pouch is the precursor of what
A
Anterior lobe of pituitary
5
Q
The branchial arches appear and disappear in what week
A
4th
6
Q
Br. Arch 1 becomes what
A
Maxillary and mandibular facial processes
7
Q
Ectomesenchyme:
Diff b/t that and normal mesenchyme
What does it form
A
Mesenchyme originating in the ectoderm germ layer
Arises from neural crest cells (from ectoderm)
Hard and soft tissues in head and neck: bones, muscles, tooth tissues (dentin, cementum, pulp)
8
Q
The place where the upper maxillary and lower mandibular processes meet at either side of the stomodeum
A
Commissura labiorum oris
9
Q
With the formation of nasal pits, the frontal prominence becomes what three facial processes
A
Median nasal facial process
R/L lateral nasal facial process
10
Q
Nasal pits do what eventually
A
Deepen to become nasal ducts
Open into stomodeum
Eventually become nostrils
11
Q
Frontal prominence becomes what 3 facial prominences
Branchial arch I becomes what 4 facial processes
A
F: median/ R lateral/L lateral nasal processes
B I: R/L maxillary
R/L mandibular
12
Q
Branchial cleft I becomes
A
External auditory meatus
13
Q
Maxillary processes become
Mandibular processes become
A
Upper part of cheeks
Lateral parts of upper lip
Lower part of cheeks
Lower lip
Chin
14
Q
Arch II becomes what
A
Operculum
(Sides of neck below auditory meatus)
Eventually, tissue that covers molars
15
Q
T/F facial processes FUSE in 4th week
A
FALSE - they merge
16
Q
Maxillary/ mandibular processes should merge by what week
A
5th
17
Q
What happens to the cardiac plate
A
Replaced by mandibular facial processes
18
Q
What happens to the buccopharyngeal membrane
A
Ruptures in 4th week
Becomes opening to foregut (nasal/oropharynx)
Membrane is the site of the pillar of fauces
19
Q
Tongue forms from what 4 lingual swellings
Which form which part of the tongue
A
L/R lateral lingual swellings
Tuberculum impar
Copula
Ant 2/3 = tub impar and lat swellings
Post 1/3 = copula
20
Q
The stomodeum divides into oral/nasal cavities when
A
6th week
21
Q
What do the following arise from:
Primary palate
Nasal septum
Palatine folds
A
Pp: from inner surface of median nasal facial process
Ns: from primary palate
Pf: from inner surface of maxillary facial processes
22
Q
T/F palatine folds merge
A
FALSE - they fuse
23
Q
Palate epithelial fusion begins when
A
Sixth week
24
Q
Mesenchymal union occurs between what 3 parts
A
Palatine folds (2) Nasal septum
25
2
2
26
Odontogenesis begins when
6th week
27
Two tissues from ectoderm primary germ layer involved in tooth development
Epithelium
| Mesenchyme
28
Formation of dentin, enamel, cementum, is called
Dentinogenesis
Amelogenesis
Cementogenesis
29
The 4 epithelial stages of odontogenesis
1. Epithelial dental lamina
2. Epithelial bud stage
3. Epithelial cap stage
4. Epithelial bell stage
30
Which of the 4 epithelial stages is the enamel organ
Epithelial bell stage
31
The two histologic stages of odontogenesis are
Epithelial
| Tooth germ stage
32
Three parts of the tooth germ
Enamel organ
Dental papilla
Dental follicle
33
The two invaginations that occur in the 6th week are the _ (facial) and _ (more lingual)
Vestibular lamina
| Primary dental lamina
34
The vestibular lamina becomes:
| The primary dental lamina becomes:
Vestibule
Epithelial part of a tooth germ
35
Epithelial buds form where
In deep end of dental lamina
36
Each epithelial bud is surrounded by
Mesenchymal tissue
37
Epithelial bud cells are continuous with _
Cells of primary dental lamina
38
Primary Central incisors time in utero
| Primary Second molars?
6 weeks
| 8 weeks
39
```
Permanent buds times:
First molar
Central incisor
Second molar
Third molar
```
4 months
5 months
10 months
5 years
40
Primary dental lamina gives rise to _ epithelial buds _ primary and _ permanent molars
16
| 10, 6
41
Each Secondary lamina arises from what
A succedaneous tooth, lingual side of primary dental lamina
42
The 4 layers of the enamel organ
1. Inner epithelial layer
2. Stratum intermedium epithelilal layer
3. Stellate reticulum epithelial layer
4. Outer epithelial layer
43
2˚ dental lamina arises from the _ NOT THE _
Primary dental lamina
| Not the oral epithelium
44
3 parts of a tooth germ
```
Enamel organ (epithelium)
Dental papilla (ectomesenchyme)
Denta follicle (ectomesenchyme)
```
45
Inner epithelial cells differentiate into _ as a part of _
Ameloblasts
| Enamel organ
46
What is reduced enamel epithelium
Enamel with ameloblasts and other layers of enamel organ that come together over the surface of the enamel as a protective structure
47
Dental papilla layer becomes what
Odontoblast
Fibroblast
Reserve cells
Ultimately becomes pulp tissue
48
Dental follicle layer becomes what
Cementoblast
Fibroblast
Osteoblast
Reserve cells
Eventually becomes periodontal ligament
49
The enamel organ is attached to both mesenchymal parts of a tooth germ by _
A basal lamina
50
What is the cervical loop
Site where inner and outer epithelial layers meet
51
The cervical loop forms a double epithelial layer called _ that serves 2 main functions
Hertwig's epithelial root sheath
Determines root dentin outline
Determines number of root canals in tooth
52
Osteogenesis Imperfecta is a type of _ condition, meaning:
Autosomal dominant
| 50% chance to show in offspring
53
Supernumerary incisor is a _ type of condition, meaning what:
Autosomal recessive
| Need 2 mutant alleles to change phenotype (2 carriers), 1/4 offspring affected
54
Amelogenesis imperfecta is a _ type of disorder, meaning:
X-linked
Affected father passes to daughter 100% of time
Affected mother passes to either son/daughter
55
Induction:
Competence:
Differentiation:
Initiating differentiation
Ability of cell to receive and respond to molecular signal
Specialization of a cell
56
3 inducers in lecture
BMP
Vit. D
Wnt signal
57
What do TF's do
Control whether genes will be transcribed into mRNA
58
DLX3 mutations lead to _ because they regulate what 3 things
TDO syndrome
1. Hair follicle differentiation
2. Enamel genes
3. Bone
59
Gastrulation is:
Conversion to trilaminar embryo (3rd week)
60
The mouth arises from _ folding
Rostral-caudal folding
61
_ cells form most of the connective tissues of the head, incl. teeth and supportive tissues
NCC ectomesenchymal
62
_ forms 8 rhombomeres
Hindbrain
63
NCCs from _ contribute to branchial arch 1
Midbrain
| Rhombomeres 1,2
64
NCCs from rhombomeres _ express hox TFs
≥3
65
Hox TFs are a type of _ which are a type of _
Homeobox TF
| TF
66
HOM-C controls what
Formation of legs (where/how many)
67
Hox genes in craniofacial region
NONE
68
Head organizing TF genes
Otx2
Msx
Dlx
Barx
69
What does branchial arch/groove/pouch 1 become
Mandible
Maxilla
Outer/middle ear
70
Treacher collins syndrome
Underdevelopment of craniofacial region and mandible due to lack of NCC migration to facial region
71
4 stages of odontogenesis
Dental lamina/Placode
Bud
Cap
Bell
72
3 characteristics of Epithelial-mesenchymal signaling
Reciprocal - Back/forth EM signals
Reiterative - Same signaling pathways again and again
Sequential - orderly sequence of events
73
Odontogenic potential is first in _ layer then _ layer later
Epithelium
| Mesenchyme
74
Dental papilla vs. dental follicle
Papilla: condensed ectomesenchyme
Follicle: surrounding ectomesenchyme
75
Primary enamel knot is what, what does it do
Non-dividing enamel organ cells in cap stage
Directs proliferation of surrounding epithelial cells
76
4 components of enamel organ at bell stage
Outer enamel epithelium (OEE)
Inner enamel epithelium (IEE)
Stratum intermedium (SI)
Stellate reticulum (SR)
77
Secondary enamel knots are present in _ stage
They appear where/do what:
Late bell
Sites of cusps (except incisors)
Direct proliferation of surrounding epithelial cells
Stimulates terminal differentiation of ondontoblasts to begin dentinogenesis
78
In the late bell stage, the _ appears
Zone of maturation
79
Dental papilla become _
| IEE become _
Odontoblasts
| Ameloblasts
80
Defects in tooth number result from _
Disruption in epithelial or mesenchymal functions in early stages of odontogenesis
81
Hypodontia:
Oligodontia:
Anodontia:
1-5 missing teeth
6 or more missing teeth
Absence of all primary or secondary teeth
82
Dentin is _ % mineral and _% organic matrix
50
| 30
83
Microscopic zones in pulp
Pulpal core
(Odontoblastic Layer)
-Cell rich zone
-Cell-free zone
84
Daily growth lines are also called _
Lines of von Ebner
85
Dentin sensitivity is mediated by
Odontoblastic processes
86
Dentin tubules in the crown have what shape?
S-shaped curvature
87
There is a higher density of dentin tubules in the _ over the _ and near the _ instead of the _
Crown over the root
| Near pulp than the surface
88
Predentin is what
Fibrillar organic matrix before its calcification
89
Primary dentin:"
Dentin made during tooth formation
| Also called circumpulpal dentin
90
Mantle dentin
Outer layer of 1˚ dentin
91
3˚ dentin forms why:
Reaction to attrition, caries, or dental restoration
92
What are the two types of tertiary dentin and what's the difference b/t them
Reactionary: formed by preexisting odontoblasts
Reparative: formed by newly differentiated odontoblast-like cells
93
Sclerotic dentin:
Transparent
94
Globular vs. linear dentin deposition
G: faster and more irregular
L: slower and more uniform
95
Interglobular dentin:
Areas of hypomineralized dentin where globular zones of mineral fail to fuse into a homogenous mass
96
Peritubular vs. intertubular dentin
PTD surrounds the tubules and is lower in collagen and higher in DSPP and more mineralized than ITD
97
ITD is harder at _ than at _
DEJ than at Pulp
| PTD is equally hard
98
DGI I occurs in people who have
Osteogenesis imperfecta
99
DGI symptoms
Discolored teeth
Attrition
Pulpal obliteration
100
DGI-III
I: with osteogen. Imp.
Brown teeth, attrition, pulpal obliteration
II: only teeth affected
DSPP mutations
Blue-grey teeth or amber brown
Enamel can split
III: multiple pulp exposures in deciduous teeth
Can be like I or II
101
DD I and II
I: mostly normal teeth but short roots
Many periapical radiolucencies
II: like DGI III
Pulp cavities show thistle tube deformity
Pulp stones
102
T/F enamel is a connective tissue
FALSE - ectoderm derived specialized epithelial cell
103
T/F enamel has an unmineralized or preenamel formation stage
FALSE - the stages of enamel are immature and mature
104
T/F Enamel formation is finite
TRUE - ameloblast completes cycle when enamel thickness is at a certain point
105
Enamel is the _ mineralized tissue to appear in a developing tooth
Second. Dentin is first
106
T/F enamel contains collagen
FALSE
107
Enamel hue depends on what 4 things
Location level
Surface conditions of enamel
Attraction to stain substances
Age changes
108
Chemical makeup of enamel
96 - inorganic substance
1 - organic substance (amelogenin)
3 - water
109
CEJ relationships
Most common:
Next most:
Least common:
Most: C overlaps E
Next: C meets E
Least: gap b/t C/E
110
Each perikymata take _ to form
8-10
111
Dimensions of enamel rod
5-6µm, length up to 2.5 mm
112
Each rod is formed by _ ameloblasts
1
113
Enamel Crystals of the _ are less dense than those of the _
Enamel sheath
| Core
114
Why are enamel rods segmented
They are secreted in a rhythmic manner (rest period)
115
What are:
Enamel lamella
Enamel tuft
Enamel spindle
Lamella: Longitudinal ribbons of hypomineralized structure
Tuft: hypomineralized claw starting at DEJ
Spindle: from dentin, a little line into enamel
116
Hunter schreager bands
Alternating dark/light bands starting at DEJ
Caused by different direction of enamel rods in adjacent layers
117
Differentiation of _ into ameloblasts and of _ into ondontoblasts begins at _
Inner epithelial cells of enamel organ
Dental papilla
Coronal most site of the future DEJ
118
Enamel stages
Secretory
Maturation
Erupted
119
3 proteins and proteinase in the secretory stage of enamel formation
Amelogenin, ameloblastin, enamelin
| Matrix metalloproteinase-20
Cleaves enamel matrix proteins
120
Proteinase in maturation stage and what it does
Kallikrein-4
| Cleaves enamel matrix proteins during late enamel development
121
Define AI
Group designation for inherited conditions displaying enamel malformations
122
3 types of AI and when the defect started
Hypoplastic (secretory stage defect)
Hypomaturation (maturation stage defect)
Hypocalcification
123
Enamel proteins and abundance
Amelogenin (85-90%)
Ameloblastin (5-10%)
Enamelin (3-5%)
124
Amelogenin does what
Organizes enamel rods during development
