Developmental biology practical Flashcards
organogenesis
During the establishment of the body plan, at the appropriate position within the embryo,
local development of organs and organ systems takes place
During the establishment of the body plan, at the appropriate position within the embryo,
local development of organs and organ systems takes place
cleavage
forms a hollow ball or disc of cells/blastula/blastoderm
gastrulation
turns the blastula into a 3 germ-layered gastrula
neurulation
special type of organogenesis - sets cells aside and forms the entire nervous system
what are the 3 germ layers of the gastrula
ectoderm
mesoderm
endoderm
ectoderm
gives rise to the nervous system
mesoderm
blood, bone, muscle and mesodermal organs
endoderm
digestive tract, respiratory tract and associated organs like the lungs and the liver
Archenteron
the future gut
3 steps in building an animal embryo
- cell division
- cells differentiation
- morphogenesis
how are genes turned off and on in cells
The turning on and off of genes in specific cells is controlled by cell specific transcription factors.
Transcription factors bind to regulatory elements called enhancers.
Enhancers influence the stable binding of the transcriptional machinery to the promoter.
MyoD
A master regulatory gene
sets up a cascade of turning on all of the genes needed for a muscle cells to become a muscle cell
what is the first event in organogenesis
neurulation
what is the first event in neurulation
the formation of a rod-like structure of mesoderm cells along the dorsal midline of the ffuture embryo called the notochord
what is special about notochord cells
they can induce (send signals to) other
surrounding cells to initiate their differentiation. Signals sent from the notochord to the
overlying ectoderm instruct the ectoderm to thicken and form the neural plate.
what happens once the neural plate is formed
it begins to fold upwards, forming neural folds. These neural folds then fuse and enclose an internalised neural tube.
Neural plate border
Separates the neural plate from the rest of the ectoderm
Neural crest
when the neural plate forms neural folds, the two ends join at what is now referred to as the neural crest.
what do neural crest cells form
they differentiate to form most of the peripheral nervous system
sonic hedgehog
an important developmental regulatory gene
plays roled in multiple developmental events eg neurulation and limb development
Wnt signalling family
The Wnt signaling
family of secreted proteins is present in all Metazoan animals (animals with an organised
body plan) and Wnt family members act in many aspects of development. I
establishing the body plan, limb
development and development of all organs.
Wnt1
The Wnt1 gene is one of the 19 genes in
the family and plays an important role in controlling development of the brain and spinal
cord in vertebrate embryos.
Pax6
paired box 6, gene encodes
a transcription factor that plays important roles in controlling patterning and development
in different regions of the central nervous system. In particular, Pax6 is known as the
master regulatory gene during eye development in all animals as diverse as vertebrates
and Drosophila.
Fgf8
Fgf8 is involved in multiple roles at all stages
of development, including mesoderm formation during gastrulation, spinal cord induction
during neurulation and limb outgrowth.
TS19
no retinal pogmentation or signs of fingers
