19.6 Flashcards
The embryo is a flat disc of cells of three layers: ___, ___ and ___
Ectoderm, mesoderm and endoderm.
The neural fold closes at different places at different times - defects of neural fold closure include ___ ___ and ___.
Spina bifida and anencephaly.
Prosencephalon = \_\_\_ Mesencephalon = \_\_\_ Rhombencephalon = \_\_\_
Forebrain
Midbrain
Hindbrain
Telencephalon = ___ and ___ ___.
Cortex and basal ganglia.
Diencephalon = ___ and ___
Thalamus and hypothalamus.
Derivatives of the neural crest include:
Peripheral nervous system (e.g. DRG, SNS/PNS ganglia, enteric ganglia, Schwann cells)!
And melanocytes, muscle, cartilage and bone of head/face, dentine.
Neural crest cells migrate down to gut to populate the enteric nervous system - failure of cells to migrate to end of gut tube causes ___ disease.
Hirschsprung’s
The neuroepithelium of the neural tube is ___ cell thick.
One/single.
In the development of the brain, stem cells start in the ___ zone, and proliferate adjacent to the ___ space.
Ventricular zone and proliferate adjacent to the ventricular space.
New cells forming at the ventricular surface migrate ___, out to skin and form new layers on the outer surface of the brain.
Radially
___ glia are a population of neuroepithelium cells that maintain connection with the ___ surface and the surface under the ___.
Radial glia
Connection with ventricular surface and surface under the ectoderm.
___ glia act as a guide for the migration of new neurons.
Radial
Radial glia are ___ cells, form some cells that form layers of brain.
Stem cells.
___ is a guide molecule that directs cells in migration from ventricular zone to outside of brain.
Reelin
Mutation of ___ results in disorders of layers of cortex
Reelin mutation -> profound mental retardation, less white matter and more grey matter.
Lissencephaly is due to mutation of the ___ gene.
Doublecortin (DCX) gene.
In ___, there is complete disorganisaion of the cortex - no white or grey matter, large ventricles, less neurons and failure of migration.
Lissencephaly
Fragile X syndrome is due to mutation of the ___ ___ ___ ___ gene
Fragile X mental retardation gene (FMR1).
There is evidence for a strong developmental component in the pathogenesis of ___
Schizophrenia
In the neural tube there is a __ plate and a ___ plate that is close to the ___.
Roof plate.
Floor plate, close to the notochord.
The notochord releases ___ ___ that diffuses out in all directions.
Sonic hedgehog
Sonic hedgehog interacts with cells in the ___ plate and induces them to change to ___ plate cells.
Floor plate -> floor plate cells by sonic hedgehog.
Floor plate cells in the floor plate release sonic hedgehog - this forms a gradient that is highest in concentration at the floor plate - neurons adjacent to the floor plate form ___ neurons in the ___ part of the spinal cord.
Motor neurons in the ventral part of the spinal cord.
Motor neurons release ___ ___ ___ that diffuses out and induces cells dorsal to motor neurons to form ___.
Motor neuron factor.
Interneurons
Growth of axons is directed by ___ ___ composed of ___ and ___.
Growth cones of actin and microtubules.
Growth cones pull axons to high concentrations of ___ (abbrev.).
NGF (nerve growth factor).
The ___ ___ refers to the time frame for refinement of synaptic connections
Critical period
Refinement
Permanent changes to form a mature and functional nervous system
If you cover a single eye of a kitten from birth and uncover it at 6 months, the kitten has ___ blindness.
Cortical i.e. normal retina and LGN, but cortex does not process information.
If you cover both eyes of a kitten from birth and uncover them at 6 months, the kitten is ___ blind.
NOT BLIND
Therefore, refinement depends on relative neural activity, NOT absolute!
