Midterm Flashcards
1
Q
Another name for patterning in early embryonic development.
A
gastrulation
2
Q
Pierre-Robin, Treacher Collins, and Marfan syndrom can all cause….
A
malocclusion syndromes
3
Q
Crouson, Apert, Pfeiffer, and many clefting syndromes can all cause…
A
craniofacial malformations
4
Q
Sclerosteosis, van Buschem’s disease, Osteoporosis-Pseudoglioma Syndrome, and Paget’s disease are all….
A
bone mass diseases
5
Q
Craniofacial anomalies account for about _____ of all congenital defects.
A
1/3
6
Q
What are the five signaling pathways used during development?
A
- Receptor Tyrosine Kinase
- TGF-beta superfamily
- Wnt
- Hedgehog
- Notch
7
Q
Which one of the these genes does NOT control homeotic selector genes?
- coordinate genes
- gap genes
- Pair-rule genes
- segment polarity genes
A
-coordinate genes
8
Q
What do morphogenes do?
A
create a gradient/balance between positive and inhibitory inductive signals
9
Q
How can symmetrical sister cells be different?
A
inductive signaling causes them to differentiate
10
Q
Two different inductive signaling mechanisms
A
- sequential induction
- morphogene gradients
11
Q
how many distinct craniofacial syndromes?
A
> 700
12
Q
The notochord, dorsal tube, and ectoderm all interact via inductive signaling with the __________ to form structures.
A
dermamyotome
13
Q
The dermamyotome gives rise to…
A
-skin and muscles
14
Q
The sclerotome gives rise to what three things….
A
ribs, vertebrae, and base of skull/some facial muscles
15
Q
Craniofacial structures are formed by what cells?
A
Neural crest cells
16
Q
Neural crest cells migrate out of regions called….
A
rhombomeres
17
Q
Tooth formation is initiated by interactions between what two cell types?
A
Ectoderm and mesenchyme
18
Q
Ectodermal dysplasias involve what five structures?
A
- teeth
- nails
- skin
- sweat glands
- hair
19
Q
What type of code drives tooth formation?
A
homeobox code
20
Q
What is more common, cleft lip or cleft palate?
A
Cleft lip (1:1000) (palate 1:2500)
21
Q
Cleft lip is more common on R or L side?
A
Left side
22
Q
A submucus cleft palate can cause….
A
bifid uvula
23
Q
Palate repair needs to be done by how many months? Why?
A
9-12 months
-speech begins to develop at 1 year
24
Q
What is the purpose of an alveolar bone graft?
A
Provide support for erupting teeth and orthodontic tooth movement.
25
What is the Robin Sequence?
combination of glossoptosis, micrognathia, and respiratory distress
26
Why lay a baby with Robin Sequence prone?
to allow tongue to fall away from airway
27
What is distraction osteogenesis?
surgical technique where new bone formation is induced by gradual separation of bony segments after osteotomy
28
What is craniosynostosis?
one or more of the fibrous sutures in infant skull prematurely fuses by ossifying and changes the growth pattern of the skull
29
Most and least common craniosynostosis?
Most common: sagittal
| Least common: lambdoidal
30
What is typically underdeveloped in syndromic craniosynostosis?
the midface
31
Pts with cleidocranial dysplasia have hypodontia or supernumerary teeth?
supernumerary
32
Gardner Syndrome causes...
osteomas all over the jaw (higher risk for colon cancer)
33
Pts with Treacher Collins syndrome are often missing...
their cheekbones
34
What is hemifacial microsomia?
one side of face is underdeveloped
35
This type of tissue is typically tightly packed and adherent cells and on the external part of the body.
Epithelia
36
These types of cells are loosely connected cells that don't interact strongly with neighboring cells. Can be very motile and respond to cues quickly.
Mesenchymal cells
37
What is the first axis formed during development? When is it apparent?
Dorsal-ventral axis apparent by the blastocyst stage
38
What week is the A-P axis established in development?
3rd week
39
The start of the primitive streak is the _______ end.
posterior
40
What drives elongation of the embryo?
convergence and proliferation of epithelial cells forming the primitive streak
41
What forms the mesoderm and embryonic endoderm (gut)
Epiblast layer that migrates through the primitive streak
42
What is created by the ectoderm abutting the endoderm at the anterior region of the bilaminar disk?
oropharyngeal membrane
43
What important structure is always located at the anterior end of the primitive streak of vertebrate embryos?
The Node
44
What is the function of The Node for embryonic development?
patterning and induction of mesoderm and embryonic endodermal cells. Establishing L-R symmetry
45
What is the purpose of the prechordal plate?
gives signals for induction of head structures
46
What does the notochord do?
provides signals for induction of neural plate
47
What part of the Node is responsible for creating asymmetry?
cilium
48
Factors of the mesoderm induce thickening of the overlying __________ to form the neural tube.
ectoderm
49
Signals from the notochord produce a _________ in the ectoderm to drive folding.
hinge point
50
What is the reason for a couple different cell populations forming in the head region?
inductive signalling
- notochord + ectoderm
- prechordal plate + ectoderm
- anterior visceral endoderm + ectoderm
51
The Lim1 gene in mice is responsible for....
head formation
52
What is the hinge point during cephalization?
the oropharyngeal membrane
53
What is concomitant with cephalization?
Folding of the whole embryo as well as specialization of foregut and hindgut.
54
During folding of the neural tube, neural crest cells will break away from their epithelial neighbors and become _____________-like.
mesenchymal like
55
After breaking off the neural tube, neural crest cells travel where?
to the ventral side of the embryo.
56
What cells are major contributors to craniofacial structure and specifically to mineralized tissues of the oral region?
Cranial Neural Crest Cells
57
What constitutes the "second wave of development" seen in vertebrates?
Neural Crest Cell migration/development
58
What are the 8 specific regions that define NCC populations and their migration?
Rhombomeres
59
Do rhombomeres determine NCC differentiation or migration?
Migration. Differentiation (structure/function) is predetermined
60
Ameloblasts, fibroblasts (pulp), and odontoblasts are all _________ derivatives, but odontoblasts and fibroblasts are also _____________ derivatives.
- ectodermal
| - neural crest
61
The pharyngeal arches begin forming in what week?
4th week (around 22 days)
62
Does the maxillary or mandibular process(es) have delayed growth?
Maxillary
63
The first pharyngeal arch gives rise to the....
mandible
64
Difference between merging and fusion?
Merging: joining of two masses already in contact (joining of maxillary prominences and lateral nasal prominences)
Fusion: joining to distinct masses (joining of maxillary nasal prominences and maxillary prominences)
65
Does a defect in merging or fusion cause cleft lips/palates?
defect in fusion
66
In what week do the Maxillary Process, Median Nasal Processes, and Lateral Nasal Processes fuse?
6th week
67
The palatal shelves come from....
the maxillary processes
68
Cranial neural crest cells primarily determine...
facial form/shape
69
In the Quck experiments, facial ectoderm develops into...
the beak/dorsal and ventral facial structures
70
What tissue is responsible for adhering during merging and fusion?
Ectoderm
71
Can cleft lip lead to defects in enamel and salivary gland function?
yes
72
What specific tissue mediates fusion of the palatal shelves?
(MEE) Medial Edge Epithelium
73
3 Causes of cleft secondary palate?
1. Poor Growth of Palatal Shelves
2. Failed Elevation
3. Failed fusion
74
Does most cartilage convert to bone in the face or the axial skeleton?
Axial skeleton (in face it mostly acts as a template)
75
Problems with the mandible are often associated with problems of the...
ear
76
The external and middle ear are derived from what pharyngeal arches?
1 and 2
77
The inner ear is derived from what pharyngeal arch?
3 (thickening of ectoderm aka otic placode)
78
The Hillocks of His are made from what kind of cell?
mesenchymal cells
79
The frontal and facial bones are of ____________ origin and and formed by ________________ ossification.
- Neural crest
| - intramembranous
80
The parietal bone is of _____________ origin and formed by ______________ ossification.
- mesodermal
| - intramembranous
81
Growth plates/centers are found in ______ bones.
long (for indirect growth)
82
What kind of control does the body have at growth plates?
genetic control
83
In order to preserve shape, parts of bone will receive new bone and parts will resorb is called....
V principle of Enlow
84
Where is endochondral growth seen?
Cranial face
85
What bone is called the "cranial base"?
The sphenoid bone
86
Can you control growth of the sphenoid bone?
no
87
This allows volume increase AND displacement in space while while maintaining proper shape of bone.
Drift Principle
88
In what cell type does intramembranous ossification occur?
vascularized mesenchyme
89
Does the maxilla or mandible have sutural growth?
Maxilla (mid palatine suture among others)
90
Are sutures growth centers or growth sites?
Growth sites (**can be manipulated with force**)
91
Are sutures genetically programmed or do they respond to function/force?
BOTH!!
92
Until age 7, the main growth of the maxilla is...
sutural growth
93
What is the first age of significant dentoalveolar growth?
7-8
94
What age range does the maxillar grow rapidly?
10-14
95
There is no more bone formation here after the incisors have erupted.
incisor region
96
The maxilla does not come forward due to deposition, but by....
displacement
97
Once sutural growth is completed by age ______, the primary method of A-P growth comes from the ___________ region.
- 10
| - tuberosity
98
Tooth roots can be considered a growth _______ because function will alter bone growth in this area.
site
99
Are the condyles of the mandible growth sites or centers?
sites
100
Can you make the mandible longer?
No
101
Can you alter the direction of mandibular growth?
yes
102
Eruption of which arch of teeth expands the maxilla/mandible?
Maxillary teeth due to their labial inclination
103
A base pair deletion can lead to a prematurely truncated protein which likely makes a _________ mutation.
loss of function
104
Loss of function of the HAPLN1 gene causes....
chondrodysplasia
105
What is considered the "gold standard" of gene sequencing? Limited to...
- Sanger Sequencing (gene by gene, exon by exon basis)
| - known gene sequences
106
What percentage of the human genome encodes for proteins?
1-2% (19,000 genes)
107
What is the most frequent genomic variant?
SNVs: single nucleotide variants
108
What is the least frequent genomic variant?
Structural changes (aneuploides)
109
NGS can detect _____ and ______ easily.
- SNVs
| - CNVs (copy number variants)
110
What are the four steps to the Variant Detection Process?
1. Sequence alignment
2. Candidate variant identification
3. Consensus calling
4. Characterization
111
What genes are associated with osteogenesis imperfecta?
COL1A1 and COL1A2
112
What condition is ENAM associated with?
Amelogenesis imperfecta
113
PHEX, DMP1, and FGF23 are genes associated with...
mineralization defects
114
PAX9 gene is associated wit...
hypo/oligodontia
115
Do we know how patterns of differential gene action will affect craniofacial growth?
NO
116
The Equilibrium Theory is an example of what part of the Matrix of Craniofacial Growth?
Environmental: alveolar bone is highly responsive to altered forces and function
117
What kind of bone do orthodontists have most control over?
Dentoalveolar bne
118
T or F: growth sites are at the diaphysis of long bones
F (at the epiphysis)
119
What kind of cells are at growth sites that allow it to be manipulated?
immature cartilaginous cells (not layered)
120
What gives faster growth, growth centers or growth sites?
Growth centers
121
Boys continue growing at the mandible level until age ___.
18 or 19
122
Age range for female growth spurts?
10-12 but max of 14
123
Age range for male growth spurts?
12-14 but up until 17
124
In order to modify growth, you must experience _____.
growth
125
What age should the orthodontists look at to determine treatment options?
Somatic age (age of the body)
126
What happens to tooth movement in someone post growth spurt?
Compensation (tooth movement) but no correction (alveolar remodeling)
127
Average amount of max growth you can stimulate in the mid palatine suture?
4-5 mm
128
Which dimension is the primary focus of orthodontists in North America?
Anterior-posterior dimension
129
The aspects of an underdeveloped maxilla?
1. not projected enough in AP dimension
2. not wide enough (transverse)
3. not low enough, did not descend enough
130
Reverse Pull Head Gear pulls on what suture?
zygomatic-temporal suture
131
Head gear slows down growth at the _________ level.
tuberosity
132
What is the function matrix?
The mix of genetics and the environment in determining craniofacial growth.
133
What is the gonial angle?
angle between the ramus and body of the mandible
