Wk.2 L2 - Brain Development - Building the Template

Question 1

LO

Answer 1

1. Describe the formation and differentiation of the neural tube and the relationship of the embryonic brain regions to the main divisions of the mature CNS
2. Describe the relationship between the neural crest and the formation of the PNS
3. Describe the relationship between neural early patterning and the formation of a simple neural circuit

Question 2

Neural identity and Neural circuits: The Spinal Cord

Answer 2

Dorsal Root Ganglion attaches to the spinal cord
* Sensory input into grey matter through sinaps’ of neuron, then out as a motor output
* Dorsal associated with sensory input
* Ventral associated with motor output

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Question 3

PNS formed from…

Answer 3

Neural crest cells migrate throughout the body and give rise to many important neural populations
- Sensory Neurons
- Autonomic Neurons
- Enteric Neurons
- Schwann cells

Question 4

Differentiation of the neural tube

Answer 4

Once the Neural tube closes, there are 3 vessicles:
1. Prosencephalon
2. Mesencephalon
3. Rhombencephaln

The Procencephalon and Rhombencephalon then subdivide into two vessicles and the optic cup, forming 5 vessicles.

5 Vessicle Stage:
* Telencephalon
* Diencephalon
* Optic Cup
* Mesencephalon
* Metencephalon
* Myelencephalon

The optic cups form neural structures of the eyes.

• Telencephalon, Diencephalon & Optic Cup = forebrain
• Mesencephalon = midbrain
• Metencephalon & Myelencephalon = hindbrain

Question 5

Derivatives of the Neural Tube

Answer 5

3 vessicle stage

V
5 vessicle stage

V
Adult brain

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Question 6

Making more cells in CNS - Ventricular Zone (VZ)

Answer 6

1. Mitotic cells replicate rapidly in the VZ
2. Radial Glia appear as first ‘post-mitotic cells’ and act as a scaffold for neurons
3. Post-mitotic neuron cells push out on the boarder creating a new zone
4. Neurons are born and begin to migrate superficially into the new zone to differentiate

Question 7

Diffusable signalling molecules set up Neural identity from early ages:

Answer 7

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The notocord releases signalling molecules called sonic headgehog
- sonic headgehog gives a ‘fate’ to cells so they know what they are once the neural tube forms