Head & Neck Development Flashcards
1
Q
- These encode RNA and proteins
A
Genes
2
Q
- What defines the identity of each cell?
A
a. Complement of RNA and protein produced
3
Q
- Ectoderm =
A
Outer
4
Q
- Mesoderm =
A
Middle
5
Q
- Endoderm =
A
Inner
6
Q
- Clinical treatments always consider what?
A
a. Form
b. Symmetry
7
Q
- The dorsal-ventral axis is apparent by what stage?
A
a. Blastocyst stage
8
Q
- During what weeks is the dorsal-ventral axis apparent?
A
a. First 3 weeks
9
Q
- When does implantation occur?
A
a. Prior to the formation of 3 germ layers
10
Q
- The A-P axis and L-R axis are determined when?
A
a. Start of week 3 with the appearance of the primitive streak
11
Q
- The A-P axis and L-R axis are determined at the start of week 3 with the appearance of what?
A
a. Primitive streak (NOT NODE)
12
Q
- The primitive streak furrows progressively elongate along the midline through the process of what?
A
a. Convergent extension
13
Q
- How does the 2nd and 3rd germ layer form?
A
a. Cells of the epiblast migrate through the primitive streak to form mesoderm and embryonic endoderm
14
Q
- Is the primitive streak formed by the mesoderm?
A
No
15
Q
- What processes form the mesoderm? (think about what this is analogous to)
A
epithelial mesenchyme transformation (EMT)
16
Q
- Do you have proportional or disproportionate growth of the germ layers?
A
a. Disproportionate
17
Q
- Why do you have disproportionate growth of germ layers?
A
a. Epiblast (ectoderm) is greater because it forms the mesoderm and endoderm
18
Q
- This is a conserved structure across all vertebrates
A
The node
19
Q
- This is the anterior-most end of the primitive streak
A
Node
20
Q
- The node is essential for establishing what?
A
a. L-R symmetry
b. Patterning and induction of embryonic cells
21
Q
- Factors secreted by cells of the Node induce anteriorly migrating mesoderm to form what?
A
a. Prechordal plate
b. Notochord
22
Q
- What germ layer forms the prechorcal plate and notochord?
A
Mesoderm
23
Q
- This is the most anterior region of the mesoderm
A
Prechordal plate
24
Q
- This provides signals for the induction of head structures
A
Prechordal plate
25
25. This is a transient epithelial-like rode structure along the midline
Notochord
26
26. This provides signals for the induction of the neural plate
Notochord
27
27. This induces and specifies the fate of the mesoderm as it is formed
Node
28
28. How do you create asymmetry in a symmetrical embryo?
a. Establish molecular symmetry
b. Conversion into asymmetric organogenesis
29
29. Nodal cells each have how many cilia?
1 motile cilium
30
30. A cilium is a membrane that helps define what property of the cilium?
a. Mechanosensory
b. Rotational
31
31. Nodal cilia have a _______ beat
Rotational beat
32
32. What helps create asymmetry because of an asymmetric distribution of morphogens?
Nodal cilia
33
33. Reproducible morphological and functional asymmetries are in nearly __________
All internal organs
34
34. This is the precursor (process) to the brain and spinal cord
Neurulation
35
35. Factors from the mesoderm induce the thickening of overlying ectoderm to form what?
a. Neural plate
36
36. Signals from the notochord induce a hinge point that helps drive
Folding
37
37. Describe the process of neural tube closure
a. Advanced maturity of anterior end → expanded neural plate → Future brain
38
38. How does neural tube closure proceed?
a. Closes anterior and posterior from the mid-region
39
39. By the end of week 3, the head and neck comprise _______ of the embryo
1/2
40
40. A defect in neural tube closure causes
Spina bifida
41
41. Cephalization =
a. Head formation
42
42. What serves as a hinge point during cephalization?
a. Oropharyngeal membrane
43
43. What 2 things are very important for the formation of the head?
a. Prechordal plate
b. Oropharyngeal membrane
44
44. Foregut and hindgut specialization occur when?
a. Folding of the entire embryo during cephalization
45
45. This is a population of “pluripotent”, stemlike cells that originate at the crest of the enclosing neural tube
a. Neural crest cells
46
46. How do NCC cells migrate?
a. Ventro-laterally
47
47. NCCs are generated by what process? This is also analogous to what?
a. EMT
b. Formation of 3rd germ layer (mesoderm)
48
48. This migrates outgrowth of the primitive tissue masses that will form much of the head and neck
CNCC
49
49. This is a major contributor to craniofacial structures and to mineralized tissues of the oral region
CNCC
50
50. (T/F) CNCCs fate is NOT determined prior to departure from the neural tube
a. False, is determined
51
51. CNCC migration pathway is reproducible? (what is this defined by)
a. Yes
b. Mesoderm
52
52. Is embryogenesis a “generative” process?
No
53
53. How can malformations and normal phenotypic variation result?
a. Single changes in gene sequence
b. Combinations of normal gene variants
c. Changes in the environment to which cells respond
