head and neck development

Question 1

emergence of the 3 body axes=
all aspects of the craniofacial complex are defined by these

Answer 1

D-V
A-P
L-R

Question 2

____encode RNA and proteins

Answer 2

genes (DNA)

Question 3

___provide the blueprint that ensures we all have a maxilla and mandible and an integrated oronasal cavity etc.
But gene mutation and differences in these non-genetic instructions determines everything about our phenotype

Answer 3

genes(genome)

Question 4

these are terms related to the embryonic origin of cells

Answer 4

ectoderm
mesoderm
endoderm

epithelia vs. meshenchyme

Question 5

clinic treatments always consider ___ and ____ because they are critical for function and esthetics

Answer 5

form (tooth shape, spacing number, etc) and symmetry

Question 6

in the first 3 weeks, these cells give rise to the embryo itself

Answer 6

inner cell mass

Question 7

this axis is apparent by the blastocyst stage

Answer 7

dorsal-ventral

Question 8

the A-P axis (head-tail) and L-R axis determined at the start of week 3 with appearance of the

Answer 8

primitive streak

(this is after implantation)

Question 9

where the embryo proper is going to form from

Answer 9

bilaminar disc AKA epiblast

Question 10

this forms when epiblast cells start to move towards each other and since they have no where to go, they start to invaginate and go inward

Answer 10

primitive streak

Question 11

epiblastic cells converge at midline and ingree which marks the

Answer 11

posterior end

Question 12

the primitive streak furrow progressively elongates along midline through the process of

Answer 12

convergent extension

Question 13

convergent extension

Answer 13

cells start to push together and extends post and ant then starts to move inward

starts at posterior end

(think about hands interlocking)

Question 14

the cells of the epiblast (layer 1 aka ectoderm) migrate through primitive streak to form

Answer 14

mesoderm and embryonic gut (endoderm)

Question 15

what is the process to form mesoderm during gastrulation?

Answer 15

epithelial to mesenchyme transformation (EMT)

Question 16

what is there a greater proliferation of because it also generates all mesoderm and embryonic endoderm

Answer 16

ectoderm (epiblast)

Question 17

this is a conserved anterior/ventral structure across all verterbraes and important in forming head structures and rest of body

Answer 17

the node

Question 18

what is the node essential for

Answer 18

patterning and induction of embryonic cells (mesoderm and embryonic endoderm)
and
establishment of the L-R symmetry

Question 19

factors secreted by cells of the node induce anteriorly migrating mesoderm to form:

Answer 19

the prechordal plate and notochord

Question 20

what is the most anterior region of mesoderm

Answer 20

prechordal plate

Question 21

what does the prechordal plate do

Answer 21

provides signals for induction of head structures

Question 22

what is transient epithelial like rod structure along the midline

Answer 22

notochord

Question 23

what does the notochord do

Answer 23

provides signals for induction of neural plate(gives rise to spinal chord and brain structures)

Question 24

this induces and specify the fate of the mesoderm as it is formed

Answer 24

the node

Question 25

creates asymmetry in symmetrical embryo

Answer 25

the node

Question 26

nodal cells each have one ______which is a membrane covered extension from the cell that has a microtubule cytoskeleton core which helps define MECHANOSENSORY AND ROTATIONAL

Answer 26

one motile cilium

Question 27

nodal cilia have rotational beat that generates leftward flow resulting in

Answer 27

asymmetric distribution of morphogens/growth factors

Question 28

neural tube formation:

Answer 28

neurulation

Question 29

what is the precursor to brain and spinal cord

Answer 29

neurulation

Question 30

during neurulation, factors from the mesoderm induce thickening of overlying ectoderm creating

Answer 30

neural plate

Question 31

during neurulation, signals from notochord induce a ___ point(floor plate) to help drive folding

Answer 31

hinge point

Question 32

the morphological difference of the anterior- most region of the neural tube reflects unique underlying cellular identities and thus

Answer 32

different inductive cues (secreted factors)

Question 33

advanced maturity of anterior end-> expanded neural plate ->

Answer 33

future brain

Question 34

by the end of week 3, what regions are comprised

Answer 34

head and neck

Question 35

this membrane serves as the hinge point for folding during cephalization

Answer 35

oropharyngeal membrane

Question 36

embryonic folding:

Answer 36

folding of whole embryo while cephalization occurs
-concomitant with formation of pharyngeal arches (>face and neck)
-foregut and hindgut specialization

Question 37

these are a unique population of stem-like cells originating at the ‘crest’ of the enclosing neural tube

Answer 37

neural crest cells

Question 38

how do neural crest cells migrate

Answer 38

migrate ventro-laterally to populate the ventral side of the embryo

Question 39

neural crest cells generated by process of ______ that is analogous(similar) to that generating the third germ layer (mesoderm)

Answer 39

EMT- epithelial-mesenchymal transformation (EMT)

kinda like gastrulation

Question 40

cranial neural crest cells migration drives outgrowth of the primitive tissue masses that will form much of the:

“second wave” of development

Answer 40

head and neck

Question 41

these are the major contributor to craniofacial structure, and specifically to mineralized tissues of the oral region

Answer 41

cranial neural crest cells

Question 42

what cells fate are determined prior to departure from neural tube aka they have “positional identities”

Answer 42

CNCC

Question 43

define distinct populations of CNCC and their route of migration into early facial tissue

Answer 43

rhombomeres 1-8, the diencephalon and anterior mesencephalon

Question 44

CNCC migration are reproducible paths of migration that are defined by

Answer 44

mesoderm

Question 45

embryogenesis is a ____process (not descriptive)

Answer 45

gernative

Question 46

malformation and normal phenotypic variation can result from

Answer 46

single changes in gene seq

combinations of “normal” gene variants

changes in the environment to which cells respond