L17- organ develoment Flashcards
describe a lung
highly branched epithelial strucuture
airways and vasculature need to devlop on a cpprdiated manner
where is the origin of cells that develop into lung
foregut endoderm
what tf code dictates lung cell fate in the foregut endoderm
Nkx2.2 in the ventral foregut
what other tf codes dictate organ cell fate of the cells of the foregut endoderm
hex/apx8/nkx2.1 = thyroid
hex/albumin - liver
pdx-1 = pancreas
where does the lung cells bud towards in the foregut endoderm
to the cardiac region
as releasing gf
when does the lung branch left and right
E9.5
right bigger
what occurs at the same time as the lung bud branches
the single foregut starts to branch into 2
forms the dorsal oesophagus and ventral trachea
what signals and tf are involved in the single foregut branching
Sox2 defines the dorsal oesoph
Nkx2.2 defines the ventral trachea
these are set up by wnt , ko wnt = no seperation of the foregut
how are all the strucutres of the lung made
through reiterative branchign
what are the phases of lung development and when do they occur
embryonic - 3-8 weeks (bronchi and bronchioles)
pseudoglandular - 5-17 weeks (+terminal bronchioles)
canalicular - 16-20 weeks (dev of respiratory
bronchioles/ b.vessel invasion starts)
saccular - 19-38 weeks , (alveolar ducts )
alveolar 23 weeks + (alveoli sacs)
What are the three models of branching
domain branching
planar bifurcation
ortholongal bifurcation
descirbe domain braching
orderly sprout of new buds at specific distance form the tip of the stalk and at position around the circumference
describe planar bifurcation
expand then bifurcate
describe ortholongal bifurcation
first bifurcate planr then twist 90 and bifurctate- rosette
in planar branching what signals control outgrowth
fgf10 in M singals through fgfr2 in epi
fgf10 also induce bmp4 which enh outgrowth
what the role of shh in outgrowth of lung branching bud
induced bby bmp4
inhibits fgf10 and bud induction
- stop excessive branch sideways
in planar branching what signals control bud arrest
fgf10 induce shh and spry2 in tip of cell
shh inh fgf10
spry2 inh fgfr in tip cell
in planar branching what signals control bud branching
bmp4 is upreg by fgf10
bmp4 inh tip cell prolif
more lateral cells bulge out and grow to new source of fgf10
describe the structure of a kidney
two main parts collecting system and nephron
what is the origin of the cells of the kidney
paraxial mesoderm induce kindey formation in intermediate mesoderm
- reciprocal signals
what does the intermediate mesoderm split into
nephrongenic cord
nephric duct
what happens to the nephric uct at E10.5
lumen all the way through
what happens to the nephrongenic cordat E10.5
part develops into mesanephric mesenchyme
what do the sigals released from the mesaphrenic mesenchyme induce
formation of the urethric bud
through MET the UB then develop into nephron epi
descirbe the reciprocal nature if renal tubule development
ub induce by mm
bud induce survival and aggregation of M
branching then regulated by factors from the mesenchyme
what signalling induces the bud
GDNF-ret
GDNF prod by m
how many generation of repeated branching do Uretric bud undergo to form the collecting ducts
10
What the role of fgf in UB branch
promote the GDNF -ret loop
what the role of wnt in UB branch
promotes GDNF production by mesenchyme of UB
what the role of BMP$ in regualting UB outgrowth
negative reg
where is GREM1 present in ub branching an the effect
at the tip cell
inh bmp4
therfore no neg reg on outgrowth
what the role of SLIT1 and ROBO2 on UB branching
inh the epi bud
what is the rike of wnt in ub branching
promotes elongation over expansion
what are teh similarities in lung and kidney branching
signal factors and mechanisms (tips and stalks)
reciprocal interactions between different tissues
regional activation / repression of signalling pathways
what are the differences in lung and kidney branching
Some of thefactors involved are different
Tissues give rise to the final organ by very different mechanisms
