Exam 5 Flashcards
(37 cards)
Gastrulation
the development of germ layers from a blastula
What are the germ layers? (3)
- endoderm
- mesoderm
- ectoderm
Endoderm (2)
- inner layer
- gives rise to digestive and respiratory systems
Mesoderm (2)
- middle layer
- gives rise to bone, muscle, and connective tissue
Ectoderm (2)
- outer layer
- gives rise to skin and the nervous system
How does the ectoderm form the nervous system?
it closes in upon itself to form the neural tube
Neural Tube
the precursor to brain and spinal cord
What are the stages of neuronal development? (5)
1) Cell Birth
2) Migration
3) Differentiation
4) Axon Growth
5) Cell Death
Cell Birth
the ventricular zone contains newly born cells that give rise to neural progenitor cells
Neural Progenitor Cells
soon-to-be brain cells
Migration (2)
- neural progenitor cells leave the ventricular zone and migrate through an intermediate zone of the neural tube before reaching their destination
- guided by the radial glial cells
Differentiation
the cell takes on the shape and function of other cells in the region
Axon Growth
chemoattractant and chemorepellent signals combine with cell adhesion molecules to guide the movement of the growth cone and its axon
Chemorepellants
prevent the developing axon from veering off course
Cell Death
several cells are lost through apoptosis
Apoptosis
programed cell death
Nerve Growth Factor (2)
- a protein that prevents apoptosis
- promotes neuronal growth
What does gray matter plasticity compose of? (3)
- axon sprouting
- dendritic branching
- neurogenesis
Synaptogenesis (2)
- the formation of synapses
- an explosive increase in synapses during the early postnatal period
Critical Period
a window of time typically in early development
Why are critical systems in early development?
it is when a system is open to structuring/restructuring
What are factors that affect critical periods? (2)
- timing
- input
Timing
biological readiness
Input
necessary to trigger the opening
