Exam 1 Flashcards
1
Q
Cleft lips start forming in what stage?
A
Embryonic stage 3-8 wks
2
Q
Cleft palates start forming in what stage?
A
Fetal development stage 9+ wks
3
Q
Zygote -> blastomere -> ?
A
Morula (> or = 32 blastomeres)
4
Q
What forms in a blastocyst and why is it a “cyst”?
A
At 64 cell stage it forms a hollow center. Cysts are hollow fluid filled pouches surrounded by tissue.
5
Q
What differentiates a blastocyst and an embryoblast.
A
Once blastocyst has inner cell mass it is an embyoblast.
6
Q
When does implantation occur? And what is the stage called?
A
Week 4. Embryoblast
7
Q
What is formed by the enlargement of the amniotic cavity and migration of cells out of the hypoblast?
A
Heuser’s Membrane
8
Q
The ectoderm is formerly the….
A
epiblast
9
Q
The mesoderm is formerly the…
A
epiblast
10
Q
The endoderm is formerly the…
A
hypoblast
11
Q
What marks the beginning of the formation of the notochord?
A
The primitive streak
12
Q
The notochord is derived from the …
A
ectoderm
13
Q
Mesothelial membranes covering peritoneal, pleural, and pericardial cavities are derived from…
A
Parietal mesoderm (from lateral plate mesoderm)
14
Q
Somites are derived from…
A
Paraxial mesoderm
15
Q
GI tract epithelium and associated glands come from what germ layer
A
endoderm
16
Q
Spina bifida and meningocele are mild, moderate, or severe?
A
Mild
17
Q
Meningomyelocele is mild, moderate, or severe
A
moderate
18
Q
Meningohydroencephalocele is mild, mod, severe?
A
severe
19
Q
Anencephaly is mild, moderate, severe, fatal?
A
Fatal
20
Q
What portion of the body is formed from pharyngeal arches?
A
Neck up to the ears
21
Q
1st branchial groove ->
A
external auditory canal
22
Q
1st branchial pouch ->
A
eustachian tube
23
Q
2nd branchial pouch ->
A
palatine tonsils
24
Q
3rd branchial pouch ->
A
inferior parathyroids/thymus
25
4th branchial pouch ->
superior parathyroids/ultimobranchial body
26
At what stage does the head size begin shrinking relative to the rest of the body?
Beginning of fetal development stage (9 weeks)
27
Cleft lip is caused by failed fusion of what two things and usually occurs 5-6 weeks of development?
Failed fusion of the medial nasal process and the maxillary process.
28
When does a cleft palate form?
8-12 weeks
29
In what direction does the palatal shelves fuse?
Anterior to posterior (4 ossification centers)
30
Is cleft lip genetically linked?
Yes, if one child has it 40% next child will
31
What do these have in common?
Ethanol, tetracycline, dilantin, lithium, methotrexate, warfarin, thalidomide, androgens, progesterone, retinoic acid, methylmercury, polychlorinated biphenyls, high levels of ionizing radiation
teratogens involved in congenital malformations
32
Where do nasopalatine duct cysts usually form?
line of fusion between palatine shelves and primary plate
33
What happens when the cervical sinus remains after the 7th week of development? And where is it found?
Turns into cervical cyst found along sternocleidomastoid muscle.
34
Where does the thyroid gland come from?
Thyroid tissue invaginates through foramen cecum on posterior of tongue and descends.
35
The tongue develops from the ________ pharyngeal arch.
1st
36
The trigeminal nerve innervates what pharyngeal arch?
1
37
The facial nerve innervates what pharyngeal arch?
2
38
The glossopharyngeal nerve innervates what pharyngeal arch?
3
39
The vegus nerve innervates what pharyngeal arch?
4
40
The hypoglossal nerve innervates what pharyngeal arch?
6
41
The trigeminal nerves innervates what part of the tongue?
sensory to anterior 2/3
42
The facial nerve innervates what part of the tongue?
taste to anterior 2/3 (via chorda tympani)
43
The glossopharyngeal nerve innervates what part of the tongue?
sensory to posterior 1/3
44
The vagus nerve innervates what part of the tongue?
sensory to extreme posterior 1/3 via superior laryngeal branch
45
The hypoglossal nerve innervates what part of the tongue?
motor to all tongue muscles
46
Median rhomboid glossitis was originally thought to be an artifact of what pharyngeal arch? (Now considered result of fungal infection)
Branchial arch II (tuberculum impar)
47
What kind of cyst is always located along the midline of the neck?
Thyroglossal duct cyst
48
Which two arches form the ear bones?
1 and 2
49
The hyoid bone is formed by what two arches?
2 and 3
50
Thyroid cartilage is formed in what arch?
4
51
Cricoid cartilage is formed in what arch?
5
52
How many auricular hillocks form the ear?
6
53
Merkel's Cartilage is from what arch and forms what bones?
Maleus, Incus, Mandible
54
Reichart's Cartilage is from what arch and forms what ear bone?
Stapes
55
Enamel is derived from what germ layer?
Ectoderm
56
Neural crest cells are responsible for what parts of tooth development?
dentin, pulp, periodontal ligament, cementum, and alveolar bone proper
57
What is thixotropy?
Ability to flow under pressure (amelogenin)
58
What is the largest enamel matrix protein?
Enamelin
59
What are the 5 stages of tooth development?
1. Initiation
2. Bed Stage (proliferation)
3. Cap Stage (prolif, differentiation, morphogen)
4. Bell Stage (differentiation completed)
5. Apposition (mineralization)
6. Maturation (calcification)
60
The neural plate structures and enamel organ differentiate from what germ layer?
Ectoderm
61
What is the dental lamina?
invagination of ectoderm (oral epithelium) into the mesenchyme
62
The dental lamina forms during what tooth development stage?
induction stage
63
On a prepared slide, an early dental lamina looks like...
a line of cells
64
What helps hold the shape of the enamel organ during the early cap stage?
stellate reticulum
65
The cells of the dental papilla end up making the...
Pulp and odontoblasts
66
The dental follicle (dental sac) ends up making the...
PDL, cementum, and alveolar bone
67
What is the first stage where ALL of the layers of the enamel organ can be differentiated?
Bell Stage
68
Outer Enamel Epithelium: cells and function
cuboidal cells, protective barrier
69
Inner Enamel Epithelium: cells and function
cuboidal cells, differentiate into ameloblasts
70
Stellate Reticulum: function
supportive function in enamel production
71
Stratum intermedium: cells and function
compress layer of flat cuboidal cells, supportive function
72
Dental Sac: structure and differentiates into what?
collagen fibers around enamel organ, diff into cementum, PDL, and alveolar bone
73
Dental Papilla: function
outer cells diff into odontoblasts, inner cells diff into pulp tissue
74
What does the cervical loop turn into in adult teeth?
The CEJ
75
What are the four parts of the enamel epithelium?
OEE, Stellate Reticulum, Stratum Intermedium, IEE
76
What structure determines the outline of the root dentin and # of roots.
Hertwig's Root Sheath (fusion and extension of OEE and IEE)
77
In teeth with multiple roots, Hertwig's Root Sheath creates ______ that divide the pulpal tissue into multiple roots.
septa
78
Why is calcification uniform in enamel but not in dentin?
Alkaline phosphatase calcifies enamel matrix as it is secreted from ameloblasts. Alkaline phosphatase is released from odontoblast tubules to calcify matrix but it is done unevenly.
79
What is the origin of ameloblasts?
inner enamel epithelial cells
80
What stimulates ameloblasts to begin secreting enamel matrix?
Mantle dentin
81
What kinds of collagen are found in the mantle dentin?
Type I and Type III
82
What makes up the Primary Cuticle?
reduced ameloblasts and remaining cells of the outer enamel epithelium, stellate reticulum and stratum intermedium
83
Difference between adodontia, hypodontia, and oligodontia
Adontia: no tooth development
Hypodontia: lack of development of one or more teeth
Oligodontia: lack of development of six or more teeth
84
What is the most common manifestation of supernumerary teeth?
Mesodens: in between 8 and 9
85
What is odontoma? When does it start?
small fragments of tooth structure consisting of dentin, enamel and cementum. Starts in initiation stage
86
What is compound odontoma?
multiple small tooth like structures
87
What is dilaceration?
abnormal angulation or bend in root
88
Difference between gemination and fusion?
Gemination: supernumerary tooth fused with a normal tooth.
Fusion: normal tooth fused with normal tooth
89
When does gemination start?
cap stage
90
What is concrescence? When does it start?
union of teeth via cementum. Occurs during the apposition stage
91
When does tubercle formation begin?
During cap stage. Gives tooth an extra cusp
92
What is a Dentigerous Cyst?
separation of dental follicle from crown of unerupted tooth. Occurs during enamel organ formation. **Know it is a dentigerous cyst b/c it is attached at CEJ
20% of all jaw cysts
93
What is the most common neoplastic lesion arising from odontogenic epithelium?
Ameloblastoma
94
What is the best form of treatment for an ameloblastoma?
Surgery. They are are radio-resistant
