Gastrulation & Neurulation Flashcards
Blasulation
Cavity forms in cell mass
What are the 3 germ layers?
Ectoderm
Mesoderm
Endoderm
Notochord function
Forms midline of gastrula
Send inductive signal s that differentiate ectoderm cells
During neurulation what fold inward?
Neural plate
What forms alongside the neural plate?
Neural crest cells
How does the neural tube form?
Edges of neural plate come together
What flexure separates the midbrain from hindbrain?
Cephalic flexure
What flexure separated the hindbrain from the spinal cord?
Cervical flexure
Describe retinoid acid
Derivative of Vitamin A
Lipophilic
RA receptor is transcription factor
Controls gene that promote differentiation
What can excessive/deficit retinoid acid cause in utero?
Birth defect
Fibroblast growth Factors bind what receptors? Which causes?
Tyrosine kinase receptors
Initiate phosphorylation cascade & Map kinase activation alters gene expression
What is fibroblast growth factors important for?
Both proliferation & differentiation
Required for development of forebrain, midbrain & spinal cord
What receptors do Bone Morphogenetic Protein activate? Which causes?
Serine Kinase receptors
- Phosphorylation cascade leads to SMAD activation
SMAD/Co-SMAD complex can alter gene transcription
What is Bone Morphogentic Protein involved in?
Initial formation of neural plate
Generation of dorsal spinal cord, hindbrain & cerebral cortex
What does Bone Morphogenetic Proteins lead to?
Skin differentiation when exposed to ectoderm
Bone differentiation when exposed to mesoderm
What blocks the skin differentiation by BMP? What does that cause?
noggin & chords
- Causes ectoderm to follow default pathway
What is the non canonical pathway important for (Wnt)?
Neural tube lengthening
Mediated by frizzled or jun receptor
What is the canonical pathway important for (Wnt)?
Cell proliferation, adhesion
Mediated by Frizzled w/ co-activation of LRP
What is the sonic hedgehog important for?
-neural tube closure
Establishment of neuron type
What is neurogenesis and where does it occur?
- Process of generating billions of neurons from few neural stem cells
- Occurs in ventricular zone
What is symmetric mitosis?
2 new neural stem cells are made
What is asymmetric mitosis?
Neural stem cell & postmitotic cell is made
How is the type of mitosis determined?
Interaction b/w delta/notch signaling
