Head and Neck Development

Question 1

______ encode RNA and proteins.

Answer 1

Genes (DNA)

Question 2

Genes (DNA) encode ____ and ____

Answer 2

RNA and proteins

Question 3

The complement of _____ and _____ produced defines the identity of each cell–its appearance and how it behaves.

Answer 3

RNA & protein

Question 4

T/F: Cells receive and process information from their surroundings –extracellular matrix, secreted molecules (growth factors) from other cells, hormones, contact with other cells (tension), nutrients, oxygen levels, etc.•These in turn modify the genes expressed, thus allowing the cell to adapt to its situation and take on new properties / behaviors.

Answer 4

True

Question 5

_______ 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 5

Genes (genome)

Question 6

_____: tightly adherent and tightly compact

Answer 6

Epithelia

Question 7

_____: loosely connected; migrating

Answer 7

Mesenchyme

Question 8

All aspects of the craniofacial complex are defined by what 3 axes?

Answer 8

• Left-right
• Dorsal-ventral
• Anterior-posterior

Question 9

Clinical treatments always consider what 2 things?

Answer 9

• form

* symmetry

Question 10

____ axis is apparent by blastocyst stage

Answer 10

Dorsal-ventral axis

Question 11

cells derived from one of two-cell embryos almost always contribute primarily to _____ tissue

Answer 11

embryonic (ICM) tissue

Question 12

descendants of the other blastomere are primarily _____ -embryonic

Answer 12

extra-embryonic

Question 13

Anterior-posterior (A-P) axis [head-tail] and left-right (L-R) axis determined at start of week ___, with appearance of the primitive streak

Answer 13

week 3

Question 14

Anterior-posterior (A-P) axis [head-tail] and left-right (L-R) axis determined at start of week 3, with appearance of the _____

Answer 14

primitive streak

Question 15

The ______ appearance definesA-P and L-Raxes

Answer 15

primitive streak

Question 16

The primitive streak appearance defines ___ and ____ axes

Answer 16

A-P and L-R axes

Question 17

Furrow of primitive streak progressively elongates along midline•through process of ______

Answer 17

convergent extension

Question 18

Cells of the _____ migrate through primitive streak to form mesoderm & embryonic (gut) endoderm

Answer 18

epiblast (layer 1)

Question 19

Cells of the epiblast(layer 1) migrate through primitive streak to form ____ and ________

Answer 19

mesoderm & embryonic (gut) endoderm

Question 20

The Epiblast layer, through process of epithelial to mesenchyme transformation (EMT), forms _____

Answer 20

mesoderm

Question 21

The Epiblast layer, through process of _______, forms mesoderm

Answer 21

epithelial to mesenchyme transformation (EMT)

Question 22

Movement of epiblast (ectoderm) to form ________ –both epithelia

Answer 22

embryonic endoderm

Question 23

Greater proliferation of ______ which germ layer because it also generates all mesoderm and embryonic endoderm.

Answer 23

epiblast (ectoderm)

Question 24

______: Anterior-most end (ventral side) of primitive streak is unique in both appearance and function; conserved structure across all vertebrates

Answer 24

Node

Question 25

_____ is Essential for: •patterning and induction of embryonic cells (mesoderm and embryonic endoderm) •establishment of the left-right symmetry

Answer 25

Node

Question 26

______ •most anterior region of mesoderm •provides the signals for induction of head structures

Answer 26

prechordal plate

Question 27

______ •transient epithelial-like rod structure along the midline. •provides the signals for induction of the neural plate

Answer 27

notochord

Question 28

The _____ Induces and specifies the fate of the mesoderm as it is formed

Answer 28

node

Question 29

The _____: Creation of asymmetry in symmetrical embryo •First establishes molecular asymmetry •Conversion into asymmetric organogenesis

Answer 29

node

Question 30

Nodal cells each have _____ mobile cilium

Answer 30

one motile cilium

Question 31

A ____ is a membrane covered extension from the cell that has a microtubule cytoskeleton core which helps define the properties of the cilium; can be mechanosensory or rotational

Answer 31

cilium

Question 32

Nodal cilia have a _______ (for a few hours only) •generates leftward flow •thought to result in asymmetric distribution of morphogens

Answer 32

rotational beat

Question 33

T/F: Asymmetric expression of morphogenetic factors (eg.SHH, BMP4 & FGF8) around Node initiates cascade of gene expression to promote asymmetric specialisation / commitment of mesoderm

Answer 33

True

Question 34

T/F: Reproducible morphological & functional asymmetries in nearly all internal organs.

Answer 34

True

Question 35

Is Embryogenesis a generative process or descriptive?

Answer 35

Generative

Question 36

______ and ______ can result from: * single changes in gene sequence * combinations of ‘normal’ gene variants, or •changes in the cellular ‘environment’ [epigenetic effects]

Answer 36

Malformation and normal phenotypic variation

Question 37

Factors from the mesoderm induce thickening of overlying ectoderm >> ______

Answer 37

neural plate

Question 38

Signals from notochord induce a _____ point (floor plate) to help drive folding

Answer 38

‘hinge’ point

Question 39

T/F: The morphological difference of the anterior-most region of the neural tube reflects unique underlying cellular identities and thus different inductive cues (secreted factors)

Answer 39

True

Question 40

Closure of neural tube proceeds ____ and ____ from mid-region (directions_

Answer 40

anteriorly and posteriorly

Question 41

By end of week ____, head & neck region comprises ~half of embryo.

Answer 41

3

Question 42

By end of week 3, head & neck region comprises ~ _____

Answer 42

half of embryo

Question 43

The ______ membrane serves as the hinge point during cephalization

Answer 43

oropharyngeal

Question 44

T/F: Folding of whole embryo while cephalization occurs •Concomitant with formation of pharyngeal arches (> face & neck) •Foregut and hindgut specialization

Answer 44

True

Question 45

a unique population of (pluripotent) stem-like cells originating at the ‘crest’ of the enclosing neural tube. •Migrate ‘ventro-laterally’ to populate the ventral side of the embryo •Differentiate into a wide variety of cell types / tissues

Answer 45

Neural crest cells

Question 46

____ generated by process of epithelial-mesenchymal transformation (EMT)that is analogous to that generating the third germ layer (mesoderm)

Answer 46

NCC

Question 47

NCC generated by process of _______ that is analogous to that generating the third germ layer (mesoderm)

Answer 47

epithelial-mesenchymal transformation (EMT)

Question 48

______ migration drives outgrowth of the primitive tissue masses that will form much of the head and neck; Unique in developmental potential (distinct from other neural crest cells)“second wave” of development(vertebrate-specific)> Major contributor to craniofacial structure, and specifically to mineralized tissues of the oral region

Answer 48

CNCC

Question 49

____ fate determined prior to departure from neural tube

Answer 49

CNCC