What are the three layers of the neural plate and there derivatives?
1. Endoderm: viscera, liver, respiratory system
2. Mesoderm: bones/muscles, excretory and circulatory system
3. Ectoderm: nervous system, sensory organs, and epidermis
True or False: Brain formation begins when the Neural Tube closes?
True
_________ _______: thickening of ectoderm on surface of the embryo
________ ________: edges of plate fold and edges grow toward each other.
_______ _________: when folds touch; cervical region 1st
_______ _________: cells adjacent to Neural Tube that separate from tube and ectoderm.
1. Neural Plate
2. Neural Groove
3. Neural Tube
4. Neural creast
_________ _________: Neural Tube Defects =inferior neural tube does not close.
________ ________ ________: ↓ Cellular proliferation.
____________: lack of Folic Acid =failure of cranial apsect of neuraltune to close.
Describe the 5 stages of Cell Proliferation resulting in 2 new daughter cells.
1. Cell in ventricular zone extends a process up to pia
2. Nucleus of call migrates up toward pial surface &DNA is copied
3. Nucleus, with 2 complete copies of genetic instructions, settles back to surface
4. Cell retracts its process from pial surface
5. Cell divides in two =
Describe the two steps of Neuron Migration:
Is cortex formed "outside-in" or "inside-out"?
Is neuronal differentiation predetermined?
1. Send slender process to brain surface and hoistselves along
2. Climb along radial glia (long cells stretching fromcenter of brain to surface)
3. "inside-out"
4. No, neurons differentiate after reaching their final location; function depends on area of brain to which neurons migrate
___________: axons growing togeter, stick together
Fasciculation
Axon guidance:
________: protein that attracts neurons in spinal cord to cross the midline
________: protein that repels the axon to grow away from the midline
1. Netrin
2. Robo
During synapse formation, what chemical "marks the spot"?
Agrin
_________ _________: Initially, each muscle receives input from several alpha motor neurons, but during development, all but one are lost. This establishes an efficient one-to-one relationship.
Synapse Elimination
_________ __________: Referring to synapse plasticity, changing from one pattern to another. Synaptic competition causes modification resulting in "neurons that fire together, wire together".
