Problem 3 Flashcards
(50 cards)
Zygote
Fertilized egg
–> has 46 chromosomes ( 50% from each parent)
(0-14 days)
The development of the zygote into an embryo
- after 12h: cell begins dividing
- after 3 days: zygote is a small mass of homogeneous cells
- after 7 days: zygote shows 3 distinct cell layers that are the beginning of all tissues
a) Ectoderm
b) Mesoderm
c) Endoderm
–> as these thicken, they grow into a flat oval plate
- Neurolation
- -> the development of the neural PLATE into neural GROOVE, then neural TUBE - Development of an embryo
Neural groove
The groove between the neural folds
Neural tube
The ridges of the neural groove come together to from the neural tube
–> has subdivisions that correspond to the future:
a) forebrain
b) midbrain
c) hindbrain
Embryo
Developing human between the 3. to 8. week after fertilization
–> after this it is referred to as a fetus
The 7 stages of the development of the Nervous system
according to lecture
- Neurolation
- Neurogenesis/Proliferation
- Cell migration/Aggregation
- Differentiation
- Synaptogenesis
- Synaptic Pruning + Neuronal cell death
- Synapse rearrangement
(8. Myelination)
Neurogenesis/Proliferation
Mitotic division of the cells of the neural tube to provide progeny cells/ neurons
Cell migration
The produced cells migrate along the radial glial cells to their appropriate regions
–> ventricular –> intermediate –> marginal region
Differentiation
The transformation of these cells into dinsinctive types of neurons + glial cells
Synaptogenesis
The establishment of synaptic connections, as axons + dendrites grow
Neuronal cell death
Selective death of many nerve cells
Synapse rearrangement
Describes the loss of some synapses + the resulting development of others in order to refine synaptic connections
–> Result: ex.: each muscle fiber comes to be innervated by only one motor neuron, not many
–> this is evident in the thinning of grey matter
Cell - Cell interaction
The general process during development in which one cell affects the differentiation of the neighboring cells
Radial glial cells
Glial cells that extend from the inner to the outer surfaces of the emerging NS
–> serve as “guide” to the newly formed cells
Cell adhesion molecules
CAMs
Chemicals that promote the adhesion of the migrating cells with the radial glial cells
Expression
The process by which the cell makes an mRNA transcript of a particular gene
–> happens when the cell reaches its destination after migrating
–> shapes the cell into the distinctive forms & functions of the neurons found in that particular region
What influences differentiation ?
- Local environment (neighboring cells)
- Intrinsic self organization
ex. : purkinje cells –> have very specific dendritic branches
Notochord
Rodlike structure that releases a protein that diffuses tp the to spinal cord and directs some cells to become motor neurons
Induction
The process by which one set of cells influences the fate of neighboring cells by secreting a chemical
Regulation
If a cell is injured or lost, other cells will fill in for the missing cells
–> compensation
Stem cell
Cell that is undifferentiated and can therefore take on the fate of any cell
Growth cones
Growing tip of a dendrite or axon
Filopodia
Fine + tubular outgrowths from the growth cone (predendrites)
–> they adhere to CAMs, then contract to pull the growth cone in a particular direction
Chemoattractants
Chemical signal that attracts certain growth cones