Cellular and Tissue-specific Origins nervous system development Flashcards
What is the origin of the entire nervous system?
Neural Stem Cells (NSCs)
Neuroectodermal origin
What regulates Neural Stem Cells (NSCs)?
Intrinsic genetic and epigenetic programs, and extrinsic stimuli
What are the two main processes of Neural Stem Cells?
Proliferation (self-renewal) and differentiation
Where are adult Neural Stem Cells primarily located?
Subgranular zone (SGZ) of hippocampus and subventricular zone (SVZ) of the lateral ventricles
What roles do Neural Stem Cells play in the nervous system?
Plasticity and regeneration
What is a characteristic morphological feature of stem cells?
Spherical morphology
Fill in the blank: Stem cells maintain a pool of stem cells through _______.
self-renewal
What type of cells can totipotent stem cells give rise to?
All cell types in a body plus extraembryonic tissue
What are examples of pluripotent stem cells?
Embryonic stem cells (ESCs)
What do multipotent stem cells give rise to?
More than one cell type
What are the characteristics of unipotent stem cells?
Can give rise to new cells of a single, specific cell type
What type of stem cells are Neural Stem Cells classified as?
Somatic stem cells (adult stem cells)
What is the Hayflick limit in relation to stem cells?
Limited proliferation
When activated, what do Neural Stem Cells replace?
Dead or damaged cells
What is the differentiation pathway during nervous system development?
NSC -> Progenitor cells -> Terminal cells
What types of cells do neural origin stem cells give rise to?
Neurons, astrocytes, oligodendrocytes, ependymal cells
What do neural crest cells (NCCs) give rise to?
Neurons and glial cells of the PNS, several non-neural cell types
What are the major processes during nervous system development?
- Neurulation
- Determination of CNS polarity and patterning
- Neurogenesis
- Gliogenesis
- Cell death
- Formation of synaptic connections
- Myelination
What is the neural tube?
The central nervous system (CNS) primordium
What are the three primary divisions of the brain during development?
- Prosencephalon (forebrain)
- Mesencephalon (midbrain)
- Rhombencephalon (hindbrain)
What are the four main heterogeneous populations of Neural Crest Cells contributing to the PNS?
- Cranial
- Vagal
- Trunk
- Sacral
What is epithelial-mesenchymal transition (EMT) in relation to neural crest cells?
Process allowing NCCs to separate from neuroectoderm and migrate
What is the role of E-Cadherin in neural crest cell migration?
Keeps cells together on epithelium
What triggers cell extrusion in neural crest cells?
Tissue stress
Fill in the blank: Placodal contribution to the PNS gives rise to sensory neurons and specializations of _______.
nose, ears, and eye
What are neurogenic placodes?
- Olfactory
- Trigeminal
- Epibranchial
- Otic
Non-neural origin CNS cell
microglia
Neural origin (NSC):
- Neurons
- Astrocytes
- Oligodendrocytes
- Ependymal cells
Neural crest cells (NCCs) give rise to
neurons and glial cells of
the PNS
- several non-neural cell
types (e.g. chromaffin cells,
melanocytes)
neural crest cells are
multipotent
Entire nervous system derives from
neuroectoderm via induction by morphogen
nervous system parts
- Neural tube (CNS)
- Neural crest cells (PNS)
- Placodes
Formation of the Nervous
System involves 3 parts
Gastrulation: local invagination of subset of cells -> ectoderm, mesoderm, endoderm
- Neurulation: formation of the neural tube (+ neural crest cells)
- Migration of neural crest cells
Prosencephalon (forebrain)
telencephalon (cerebrum)
diencephalon (thalamus +
hypothalamus)
Rhombencephalon (hindbrain)
Metencephalon (pons + cerebellum)
Myelencephalon (medulla)
Epithelial-Mesenchymal
Transition (EMT)
bottom pic
After induction, the NC is
physically separated from the
neuroectoderm by delamination
Mesenchymal behavior (collective
migration)
PIEZO1
top pic
Stretch-activated channel
Piezo1 stimulates extrusion
via activation of actin-myosin
contraction
Cell extrusion = a cell is
forcefully expelled from an
epithelium by neighboring cells
- structural rearrangement of
the cytoskeleton
based on gating mechanism, PIEZ01 is
mechanically gated
