Task 3: Brainy Methods Flashcards
Notes & lecture & article (36 cards)
Zygote
fertilised egg (containing 46 chromosomes with genetic recipes for the development of a new individual)
Discuss the development from zygote to neural tube
- 12 hrs – single cell begins dividing
- 3 days – small mass of homogeneous cells
- 1 week – emerging embryo shows 3 distinct layers
- > Ectoderm – outer cellular layer that develops into skin & NS
- > Mesoderm
- > Endoderm
- 20 days – neural groove begins to develop (becomes midline, groove between neural folds)
- 22 days – neural groove closed to form neural tube
Discuss how the neural tube develops into the subsections of the brain
24 days – at head end of neural tube, fore-, mid- & hindbrain become apparent
- > Forebrain (prosencephalon = telencephalon + diencephalon)
- > Midbrain (mesencephalon)
- > Hindbrain (rhombencephalon = metencephalon + myelencephalon)
When does the embryo become a fetus?
10 weeks
When do the major brain regions develop?
11 weeks
Name the 6 developmental stages of the nervous system
- neurogenesis
- cell migration
- differentiation
- synaptogenesis
- neuronal cell death
- synapse rearrangment
Neurogenesis
production of nerve cells
Cell migration
movement of cells from site of origin to final location
Adult neurogenesis
generation of new neurons in some areas of the adult brain (mostly hippocampus and olfactory organ)
Radial glial cells
extend from inner to outer surface of emerging nervous system (spanning width of emerging cerebral hemispheres) and guide migrating neurons
-> New neurons creep along them to higher layers of cortex
Cell adhesion molecules
protein on surface of a cell, promote adhesion of developing NS elements, guide migrating cells & growing axons
-> May also guide axons to regenerate when cut in adulthood
Cell differentiation
once cells reach destination they express genes (i.e. transcribe a particular subset of genes to make the specific proteins they need)
2 influences on cell differentiation
- Cell-autonomous differentiation:directed by cell itself (intrinsic self-organization) rather than influence of other cells, only the genes within the cell are directing events
- induction: cell-cell interaction – one set of cells influences the fate of neighbouring cells
Synatogenesis
establishment of synaptic connections as axons and dendrites grow
Process outgrowth
extensive growth of axons and dendrites
Growth cones
specialised swellings (growing tip) of an axon/ dendrite -> dendritic cones – found in adults, mediating the continued elongation + change in dendrites that occurs throughout life in response to experience
Filopodia
fine tubular outgrowths from the growth cone
-> adhere to CAMs in extracellular environment and contract to pull cone in particular direction
Chemoattractant
attract particular classes of axonal growth cones
Chemorepellents
repel particular classes of axonal growth cones
Neural apoptosis
death of many neurons as normal part of development for synaptic pruning
Death genes
case cells to actively decied to die and commit suicide (carried by chromosomes and released when they die)
Neurotrophic factor
target derived chemical that acts as if it “feeds” certain neurons to help them survive – neurons that receive enough survive, those that don’t die
Nerve growth factor
substance that markedly affects growth of neurons in ganglia of sympathetic NS
Synaptic pruning
refers to the process by which extra neurons and synaptic connections are eliminated in order to increase the efficiency of neuronal transmissions.
