Development of the Nervous Systems Chapter 3 Flashcards
How many stages are there in the development of the nervous systems?
6
what are the stages in the development of the nervous systems?
- Dorsal induction
- Ventral induction
- Neural Proliferation
- Neural Migration
- Cortical organization and Synapses Formation
- Myelination
When is the Dorsal induction ?
GA : 3-7 Weeks
what happens in Dorsal induction?
The neural Tube is formed
in the Dorsal induction how is the neural tube formed?
GA week 3 : the posterior part gets thick and Neural plate is formed
GA week 4: Neuroplate wraps around to form the euro tube
GA week 6: Both ends of the Neuro tube will close
what does Neurulation mean?
the Neuraltube wrapping around each other
What develops out of the neural tube?
The central nervous system
Why is dorsal induction such a critical period?
For the central nervous system to develop
What are three embryonic errors ?
- encephalopathy
- anencephaly
- spina bifida
when does ventral induction happen?
GA: 2-3 months
What happens during ventral induction ?
the face and brain develop out of superior end of the tube
what does Corpus Callosum mean ?
Dividing two hemispheres between and between the hemispheres will develop
in the Ventral induction what are the 3 primary divisions ?
- Prosencephalon
- mesencephalon
- rhombencephalon
what are the 2 secondary divisions of Prosencephalon?
- Telencephalon
2. diencephalon
What does Telencephalon make?
Cerebral Hemisphere
what are the 4 things diencephalon make?
- epithalamus
- thalamus
- hypothalamus
- neurohypophysis
what is the secondary division in mesencephalon?
mesencephalon
what does mesencephalon make ?
Midbrain
where is mesencephalon?
superior part of the brain stem
What are the 2 secondary division in rhombencephalon ?
- Metencephalon
2. myelencephalon
what does Metencephalon make?
Pons cerebellum
what does myelencephalon make?
Medulla
where is the Medulla ?
Most inferior part of the Brain stem
when does the Neural Proliferation happen?
GA: 3-4 months
What happens during Neural proliferation ?
Birth of new neurons
Glial cells
what do Glial Cells do?
help support the neurons
what are neurons ?
Main cells of the nervous systems
What is an abnormality that could happen ?
Microcephaly
what is Microcephaly ?
Small head
When is Neural Migration ?
GA 3-5 Months
what happens during Neural Migration?
Neurons move into the correct position
Development of Guyri and Sulci
What is Chemical Reelin do during Neural Migration?
signals neurons where to stop
During Neural Migration at 20 weeks what happens?
process stops and 6 layers of cerebral cortex are established
When does Cortical organization and Synapses Formation happen?
GA: 5 months to years
What happens during Cortical organization and Synapses Formation?
Synapses start to form and make neurons communicate with each other
what is is called where Dendrite and Axons start to Communicate
Synapses
When is Myelination ?
GA: Birth to years
what happens during Myelination ?
Neuron Axons are coated with Myelin
what is Myelin ?
fatty material
what happens when the Axons are coated in Myelin ?
Makes signals from the nerve faster
