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Flashcards in Nervous System Development II Deck (23):

What happens to the pineal cord around the 11th week of gestation?

- It begins to REGRESS form the CAUDAL portion of the spinal cord

- This forms the CAUDA EQUINA


What does the regression of the spinal cord provide?

A safe place to withdraw CSF


Spinal cord gray matter organization

- Central

- Ant./Post./Lat. Horns

- Horns situated around a Central canal


Brain gray matter organization

Deep areas are rep. By the Basal Nuclei and other nuclear groups


Brain white matter organization

Myelinated FIBER Tracts throughout various parts of the brain

Lie superficial to the gray matter


T/F: in the Cerebrum and Cerebellum, additional EXTERNAL areas of Gray matter (The Cortices) are built on top of (External to) the myelinated white matter.



Classical Def of a Cerebral Cortex

- Multiple Layers of gray matter (6)

- Built from the INSIDE OUT

- Most superficial layer added last


Exceptions to the Cortex growth rule

- Neuronal Migration

- Cerebellar/Cerebral cortices have only 3 layers

- Some parts of the cerebral cortex are built from the Outside IN


Role of Radial GLIAL cells in the building of a cortex

- Extends long process that passes through the

1. Intermediate Zone
2. Cortical Plate
3. Marginal Zone (Outermost)

To the SURFACE Of the brain


*The topographical arrangement of the Myelen-Cephalon is almost identical to the spinal cord.

What is the MAJOR Topographical change?*

- Pronounced expansion of the ROOF PLTE

- To form the thin roof over the FOURTH ventricle


*Expression of which set of genes seems to be responsible for the differentiation of Specific nuclei in the Myelen-Cephalon?*

Hox genes


*What are the major derivatives of the Meten-Cephalon?*

- Pons (Basal plate)

- Cerebellum (Alar plate)


*The Cerebellum forms in the region of the RHOMBIC Lips (1-8). The lips are the product of what Inductive Interaction?

Roof plate and Neural Tube via BMP Signaling


*Migration of cells that will for the Cortex in the Cerebellar Primordium *

1. Granule cells Migrate ANTERIORLY along dorsal region of Rhombomere 1

2. Then Migrate INTERIORLY through Purkinje layer

3. Purkinje cells Migrate RADIALLY through Granular cells


*What are the Superior Cerebellar Peduncles?*

Massive FIBER bundles b/w the Cerebellum and the MESEN-Cephalon


*What are the Major derivatives of the ALAR plate of the Mesencephalon?*

Tectum (Corpora Quadrigemina)
- Sup/Inf Colliculi


*Where is Oti-2 located and how is it related to SHH?*

Confines SHH to the BASAL part of the MIDBRAIN


*Where do the Cerebral Peduncles form and what is their fxn?*

1. Ventro-Lateral region of the MESEN-Cephalon

2. Carry fibers b/w the Cerebral HEMISPHERES and the Spinal Cord


* What are the Major derivatives of the Diencephalon?*

- Epithalamus

- Thalamus

- Hypothalamus


*What are the THREE Patterning centers in the Forebrain?*

1. Rostral (FGF-8)

2. Dorsal (BMPs and Wnts)

3. Ventral (SHH)


How many Cranial nerves are there?



Why are CN I and II not True Nerves?

They Do not join with the BRAINSTEM


What is Rachischisis?

- The brain is NOT covered by cranial bones

- The spinal cord is totally exposed