Limb Development Flashcards
Which molecule instructs the dermatome to become dermis?
Neurotrophin 3
Sonic hedgehog and noggin induce formation of which somite derivative?
Sclerotome
What is the lateral somatic frontier?
The conceptual barrier between each somite and the lateral plate ,mesoderm, it separates the somite derived primaxial domain and the lateral plate mesoderm derived abaxial domain
The border between the dermis derived from dermatome and the dermis derived from the lateral plate mesoderm is defined by…?
Lateral somatic frontier
Where do primaxial signals come from?
Neural tube and notochord
Where do abaxial signals come from?
Lateral plate mesoderm
Epaxial muscles are innervated by dorsal primary rami. T/F?
True
Hypaxial muscles are innervated by dorsal primary rami. T/F?
False - they are innervated by ventral primary rami
What factors of a cell can be affected by differentiation?
Cell size, shape, membrane potential, metabolic activity and responsiveness to signals
At the end of which week in development do the limb buds appear?
Week 4
When does limb morphogenesis take place?
Weeks 4-8
The lower limbs differentiate before the upper limbs. T/F?
False the opposite is true
What is mesenchymal connective tissue composed of?
A matrix of collagen fibres, hyaluronic acid and glycoproteins
What do the limb buds consist of?
Mesenchymal core from the parietal layer of the lateral plate mesoderm covered jn a layer of cuboidal ectoderm
What is the name of the thickening of the distal ectoderm border of the limb bud?
Apical ectodermal ridge
The secretion of what, initiates limb outgrowth?
FGF10
Which signalling molecule is expressed by the dorsal ectoderm of the limb bud?
Radical fringe
Which transcription factor is expressed on the ventral side of the limb bud?
Engrailed 1
Which factors are essential for the maintenance of the undifferentiated zone of the apical ectodermal ridge?
FGF 4 and 8
The AER and mesoderm of the limb bud have an inductive relationship. T/F?
True
During which week of development do the terminal portion of the limb buds become flattened into hand and foot plates?
Week 6
Constrictions divide the limb bud into three segments which will go on to become the arm/thigh, forearm/leg and hand/foot. T/F?
True
What is the order of the developmental components of the limb buds which will become the arm/thigh, forearm/leg and hand/foot, from most proximal to most distal?
Stylopod
Zeugopod
Autopod
The positioning of the limbs along the craniocaudal axis is regulated by which family of genes?
HOX genes
