L14 head development

Question 1

where are the nasal placodes in 28-33d of develoment

Answer 1

on frontal prominence

Question 2

what celluar/dev processes occur to shape strucutres that develop from nasal placodes
what strucutres are they

Answer 2

proliferation
cell migration
maxillary/mandibular/frontal prominence

Question 3

what do nasal placodes devleop into

Answer 3

pits surrounded by medial and lateral nasal wellings

Question 4

what do the lateral nasal sweeling develo into

Answer 4

nostril

Question 5

what do the mandibular processes devleop into

Answer 5

the lower lip

Question 6

how is upper lip formed

Answer 6

maxillary swelling grows
compresses medial nasal welling
then fuse

Question 7

what day is the mammalian face recognisabel

Answer 7

47

Question 8

when did NCC and skull ev

Answer 8

510mya

Question 9

where cells form the head

Answer 9

ncc
paraxial mesoderm
endoderm
ectoderm

Question 10

what cells and what process is the neurocranium/vault formed by

Answer 10

intramembraneous ossification within mesenchyme

NC and mesoderm

Question 11

what cells and what process is the viseroanium/base formed by

Answer 11

intrambnous ossif
Endochondral ossif
NC +mesoderm

Question 12

what cells and what process is the viscerocranium/facial bones formed by

Answer 12

ncc

intrambnous ossif

Question 13

what is the differnece between endochondral ossif and intramembraneous ossif

Answer 13

eo - via a cartilage intermediate/slower

Question 14

what is special abut face dev

Answer 14

from ncc

diff from axial skel

Question 15

where ncc from and what process imp

Answer 15

developing n.tube migrate to head/neck primordia

EMT

Question 16

what dictates the migration of ncc

Answer 16

tf

Question 17

what tf do ncc that migrate to the head expr

neck expr

Answer 17

non-Hox homeodomain pr e.g. Otx

Hox expr

Question 18

what is the differnece in differentiation between cranial ncc and trunk ncc

Answer 18

trunk can not develop into skeleton precursos eg chondrocytes and osteoblasts
both - melanocytes/neurons/glial/endocrine/connective

Question 19

where do ncc arise from

Answer 19

at jucntion of neural plate and surface ectoderm

Question 20

what specifices the postion of the ncc in rhomobomeres

Answer 20

hox code

Question 21

where do the ncc in teh rhomobomeres migrate to

Answer 21

into mesenchyme of face and branchial arches
diff rhombo contribute diff ba (in segmental streams)
(r1-3=ba1)

Question 22

what do the experiments transplant wrong rhomobomere into ba what show

Answer 22

if put r4 into ba1 get ectopic arch strucutre

ncc pre pattern

Question 23

what evidence is there for plastcity in ncc cells

Answer 23

transplant allow to mix with neighbour cell change in gene expr seen

Question 24

what strucuteres in neck and face do ncc contribute

Answer 24

face - mandibular and maxillary

neck - PA

Question 25

what intrinsic factors pattern the head

Answer 25

Hox code along the AP axis of BA
eg PA1 no hox, pa2 hoxa2/b2, pa3 etc
dlx code along the DV axis
eg dorsal = dlx1/2, dlx1/2/5/6 etc

Question 26

ehat the ptype of a hox mut and hoxa2 mut

Answer 26

hox mut - chnage or loss of skeletal strucutres
hoxa2 - dup of ba1 strcutres/inh intrambn ossif
deafness

Question 27

what ptype of a dlx5/6 mut

Answer 27

loss of facial strucutres and decr bone strucutre

Question 28

what extrinsic factors involved in the patternign of the head

Answer 28

fgf/bmp/wnt/endothelin

role in inducing specific programmes

Question 29

what is the role of fgf8 in patternign

Answer 29

nec for craniofacial dev
is a ncc survival factor
gives positional info for lhx6/7 homeodomain

Question 30

what is the role of bmp in patterning of the head

Answer 30

induces endothelin 1 expr

which induces dlx gene

Question 31

what is the role of runx2

Answer 31

master regulator for osteogenesis via intramembraneous ossif

Question 32

what signal intergrte to control regulate runx2

Answer 32

bmp induce edn induce dlx expr
dlx promote runx2
wnt upreg runx2

Question 33

what the role of sox9

Answer 33

master regulator for chondrogenesis

Question 34

what is the phenotype of trecher collins syndrome ncc

Answer 34

fail to prolif but do migrate to correct place

Question 35

what the molecular mechnaism behind the TCS phenotype that results from TCOF1 mut

Answer 35

truncation in treacle pr
treacle has role in rna biogensis
decr treacle = decr prolif as less rna

Question 36

how can recue tcof1 phenotype

Answer 36

remove one copy of p53
(promotes cell death)
p53 norm decr cell proli via bind sl1 and destabilise the interaction with ubf

Question 37

what is the ncc ptype in bardet biedl syndrom

Answer 37

ncc fail migr