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11b-Developmental neurobiology - Coggle Diagram

- - - - Aggregation into ganglia
        
        Migration in the trunk
        
        Following induction, neural crest cells migrate away from the neural tube
        
        Nueral crest cells follow various pathways to their target sites
        
        Cells that will form the sympathetic ganglia migrate to dorsal aorta
        
        Forms: Dorsal root ganglia, sympathetic ganglia, pigment cells and adrenal medulla
        
        Formation of sympathetic chain ganglia
        
        Neural crest migration to the dorsal aorta.
        
        Cells are dispersed along aorta (no segmentation)
        
        Cells aggregate into discrete ganglia
        
        Cells aggregate together into ganglia (collections of cell bodies)
      - Axon guidance
        
        Axon Extension: The axons of sympathetic ganglion neurons extend from the cell bodies within the ganglia to reach their target organs and tissues throughout the body. This extension is guided by molecular cues, often in the form of signaling molecules, which can attract or repel axon growth.
        
        Chemotaxis: Chemotaxis is the process by which axons are attracted or repelled by chemical gradients. In the case of sympathetic ganglion neurons, guidance cues, such as nerve growth factor (NGF) and semaphorins, help steer axon growth. NGF, for example, acts as a chemoattractant, encouraging axons to grow toward their target tissues.
        
        Axon Fasciculation: Axons from multiple sympathetic ganglion neurons often grow together in bundles, a process known as fasciculation. This bundling helps them maintain a coordinated path and reach their target organs efficiently.
        
        Synapse Formation: Once the axons reach their target tissues, they establish synapses with the effector cells (e.g., smooth muscle, cardiac muscle, glands). This is a critical step in the functional integration of the sympathetic nervous system with its target organs.
    - - Development
        
        The border region between the neural plate and ectoderm is induced to become neural crest
        
        Neural crest cells express different genes to neural plate/neural tube
        
        They undergo a process of epithelial-mesenchymal transition to allow them to break free from the neural tube and migrate
        
        Neural crest form neurons and glia of PNS, and many other cell types (e.g Dorsal root ganglia, symp and para ganglia and enteric nervous system
      - Epithelial-mesenchymal transition
        
        Involves changes in:
        
        Cell-cell adhesion
        
        Polarity
        
        cell shape
        
        Cell-matrix adhesion
- - - - Plasticity
        
        Most symp ganglion neurons use noradrenaline as a neurotransmitter
        
        Some use acetylcholine
        
        Some neurons change phenotype (e.g from adrenergic to cholinergic
    - - Myelination and glia in the periphery
        
        Glia location in PNS
        
        Schwann cells and satellite cells develop from neural crest
        
        Tumours from PNS
        
        Gives rise to neuroblastoma.
        
        Most commonly develops from neuroblasts in the adrenal medulla
        
        Most common solid tumour in childhood