Lecture 3 Flashcards
Neurulation
Form neural tube after neural induction
Neural Tube Patterning
Subdividing tube into forebrain, midbrain, hindbrain, spinal cord
How central nervous system regions are determined (2 steps)
Spatial patterning via positional cues
Allows cells to choose different fates
1. Activator instructs cells to choose neural fate
2. Transformer specifies different regions in concentration dependent manner
How 3 germ layers are formed
During gastrulation blast ERBs move to change positions to produce the layers
This is an example of Cell-Cell signaling
Iterative process
One event triggers the next (fate is determined by the new neighbors)
Morphogen
Non-uniform distribution governs the pattern of development during morphogenetic or pattern formation to establish positions of the various specialized cell types within a tissue
Local Patterning- Rhombomeres
Transiently divided segments
- constricted swellings in neural tube
- develop own set of neurons and nerves
Parasegments
Developmental units
Formed by posterior half of one and anterior half of the adjacent
Extrinsic Cell-Cell Signaling
Secreted factors (gradient) Cell-cell communication(like ligand and receptor)
Intrinsic Cues of Cell Lineage
Asymmetric Cell division Temporal regulation (birth order)
Formation of External Sensory Organ
Sensory organ precursor undergoes three rounds of asymmetric cell division to form organ with 4 different cells
Nueroblasts
Neural stem cells in Drosophila embryonic CNS that can generate a series of different neural cells called ganglion mother cells
How do Neural Stem Cells generate different neurons throughout neurogenesis
Lineage
They make different neurons at different times
