L20 Organogenesis Flashcards
List the order of events of Developmental Embryology that give rise to an Embryo
Fertilisation, Cleavage, Gastrulation, Neurulation, Organogenesis
what is cleavage stage known as?
8-cell stage
what is a type of organogenesis?
neurulation
what is meroblastic give example
yolk stays intact example zebrafish
what is holoblastic give example
yolk is divided amongst nearby cells example humans
what does ectoderm later form?
neurons, skin, pigment cells
what does mesoderm later form?
somites, heart, mesenchyme, mesothelium, non-epithelial blood cells and coelomocytes
what does endoderm later form?
lungs, pharynx, esophagus, stomach, small intestine, colon, liver, pancreas, bladder, thyroid
how is gastrulation characterised
interaction of cells across 3 distinct germ layers
how is organogenesis characterised?
local interactions that allow definition and development of an organ - forming tissues
morphogenesis of structures
what morphogenic structures occur during organogenesis?
folding of neural tube, looping of heart, branching of lungs
what cells make the germ layers?
STEM cells/ somatic cells
what are germ cells?
sex cells
How does nervous system form?
on outer embryo body and then becomes internalised
what is notochord derived from?
dorsal lip of blastopore
how does neural plate form?
notochord signals ectoderm layer to thicken
what signalling molecule is secreted from notochord and is key in neural plate synthesis?
shh
where are neural crest cells?
above neural plate
what do neural crest cells give rise to?
PNS
where and how does a neuron undergo to specialise as a neuron cell?
undergoes neurogenesis in CNS
What signalling pathway has a role in lateral inhibition?
delta-notch pathway
what does delta-notch signalling pathway do?
inhibits neighbouring cells from differentiating
why is hox code neccessary?
to ensure the right shape of vertebrate forms in the right place
what happens if hox code is changed?
nerve projection changes
what is the fate of somite cells?
muscle blocks of body wall and vertebrate of backbone
how does spatial organisation occur
?
cells are influenced by multiple cell signals in embryo
what does lateral plate mesoderm split into?
dorsal and ventral cavity formed in between called coelom cavity
dorsal side of mesoderm plate forms
body wall (with overlying ectoderm)
ventral side of mesoderm plate forms
heart and circulatory system
what is the first functioning organ?
heart
what is mesenchyme
a tissue organisation where cells are loosely connected to one another
what does mesenchyme differentiate into
circulatory system, connective tissue, cartilage and bone
what changes heart from tube morphologically?
looping and septation
key pathway in heart formation
BMP, Tbox TF, Wnt, Notch
What does BMP do?
controls expression of an important TF needed to differentiate heart muscles Nkxx2.5
what are 2 neccessary systems for development
extensive branching morphogenesis and mesenchymal to epithelial transition
what is vasculogenesis
angioblast cells assemble into vessels thorugh mesenchymal to epithelial transition
what are the 2 phases of blood production?
embryonic phase and definitive phase
what are stem cells in bone marrow called?
haematopoietic stem cells
what tubes does endoderm produce during folding?
digestive and respiratory tract
what 2 signalling pathways work together for branching of lungs?
fgf-10 (induces branching) and shh (limits outgrowth)
