Neurodevelopment Flashcards
What did Seneca believe?
That development was just miniature versions of creatures growing bigger (preformation).
What is similar in all vertebrates?
The embryonic nervous system.
What are the three chambers of young vertebrates?
- Forebrain
- Midbrain
- Hindbrain
What forms the spinal cord?
Remaining neural tube.
What happens on day 1 of development?
The human zygote consists of a single cell.
What happens on day 2 of development?
The cell divides and continues to divide.
What happens on day 15 of development?
The emerging embryo is formed by several sheets of cells with a raised area in the middle called an embryonic disc.
What happens on day 21 of development?
Primitive neural tissue forms the neural plate.
What is the neural plate?
The neural plate gives rise to the neural tube. Nursery for the rest of CNS. Also gives rise to the brain’s ventricles and spinal canal.
What happens on day 49 of development?
The embryo resembles a miniature person.
What happens on day 100 of development?
The brain begins to resemble that of a human.
What happens on month 7 of development?
Formation of gyri and sulci.
What happens on month 9 of development?
Very distinct human brain, although cellular structures is still much different than adult brain.
What are neural stem cells?
They are cells that have yet to choose a type (multipotential). They have great self-renewal.
Where are the neural stem cells?
They line the neural tubes and form the subventricular zone.
What do the stem cells create?
They give rise to progenitor cells (precursor cells).
What do progenitor cells become?
- Neuroblasts
- Glioblasts
What cell can divide infinitely and what cell can divide limitedly.
Infinite: Stem cells
Limited: Progenitor cells
What are neuroblasts?
They will develop into neurons.
What are glioblasts?
They will develop into mature glia.
What happens after the blasts?
The blasts specialize into mature neurons/glia.
What do newborn cells use throughout the development process?
Chemical signals and genetic instructions.
What are the three ways to ensure stem cells become mature neurons/glia?
- Prolactin
- Genetranscription
- Epigenetics
What is prolactin?
A naturally occurring hormone that helps replace lost neurons in animal models. If you put it in the brain it will signal to start neurogenesis.
How does gene transcription work?
A turning on the correct genes that dictate a stem cell will become a neuron and not a skin cell.
What is epigenetics?
Epigenetics is gene silencing.
What is DNA methylation?
DNA methylation is a methyl group stopping a ribosome from transcribing.
What are neurotrophic factors?
Chemical compounds that act to support the growth and differentiation of neurons.
What are the two neurotrophic factors?
- Epidermal Growth Factor (EGF)
- Basic Fibroblast Growth Factor (bFGF)
What are epidermal growth factors?
Stimulate stem cell to produce progenitor cells.
What are basic fibroblast growth factors?
Stimulate progenitor cells to produce neuroblasts.
What are the neurodevelopment stages? (7)
- Cell birth
- Cell migration
- Cell differentiation
- Cell maturation
- Synaptogenesis
- Cell death
- Myelogenesis
Cell birth? (neurogenesis)
Birth of neurons by 5-month-olds.
Cell migration?
After neurogenesis. About 6 weeks.
Cell differentiation?
During migration and continues after. Almost complete by birth.
Cell maturation?
Growth of dendrites and axons. It continues for years, into adult years.
Synaptogenesis?
Neurons start to form their own networks.
Cell death?
if you don’t use it you lose it.
Myelogenesis?
Neuronal networks become more efficient in their communication. Sign of neurodevelopmental maturity, occurs well into adulthood.
How do cells get their destination?
- Subventricular Zone
- Radial Glia Cells
What is the Subventricular Zone?
-SVZ contains a primitive map of the cerebral cortex;
-Cells formed in certain regions of the SVZ migrate to certain cortical locations.
What are radial glia cells?
-Form a path that extends from the SVZ to the surface of the cortex;
-Undifferentiated progenitor cells follow this path.
What signals restrict the choice of traits a cell can express?
Intercellular signals.
What is the combination that determines the emergence of a cell type?
Genetic instructions, timing, and signals from neighboring cells in the local environment.
What do maturing neurons need?
- Dendrites
- Axon
What are the two parts of cell maturation?
- Growth cones
- Filopods
How do growth cones and filopods work together?
Growth cones extend filopods and when a filopod reaches an appropriate target the others follow.
What are growth cones responsive to?
- Cell adhesion
- Tropic molecules
What does the brain use for synaptic pruning?
Cell death or apoptosis.
What neurotrophic factors do cells use to regulate neuronal survival?
Nerve Growth Factor
What is the last region to myelinate?
The frontal lobe.
What can be used as an index of neuronal maturity?
Process of myelination
