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Flashcards in Nervous System Development II Deck (23):
1

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

2

What does the regression of the spinal cord provide?

A safe place to withdraw CSF

3

Spinal cord gray matter organization

- Central

- Ant./Post./Lat. Horns

- Horns situated around a Central canal

4

Brain gray matter organization

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

5

Brain white matter organization

Myelinated FIBER Tracts throughout various parts of the brain

Lie superficial to the gray matter

6

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.

True

7

Classical Def of a Cerebral Cortex

- Multiple Layers of gray matter (6)

- Built from the INSIDE OUT

- Most superficial layer added last

8

Exceptions to the Cortex growth rule

- Neuronal Migration
(Parallel)

- Cerebellar/Cerebral cortices have only 3 layers

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

9

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

10

*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

11

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

Hox genes

12

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

- Pons (Basal plate)

- Cerebellum (Alar plate)

13

*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

14

*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

15

*What are the Superior Cerebellar Peduncles?*

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

16

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

Tectum (Corpora Quadrigemina)
- Sup/Inf Colliculi

17

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

Confines SHH to the BASAL part of the MIDBRAIN

18

*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

19

* What are the Major derivatives of the Diencephalon?*

- Epithalamus

- Thalamus

- Hypothalamus

20

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

1. Rostral (FGF-8)

2. Dorsal (BMPs and Wnts)

3. Ventral (SHH)

21

How many Cranial nerves are there?

12

22

Why are CN I and II not True Nerves?

They Do not join with the BRAINSTEM

23

What is Rachischisis?

- The brain is NOT covered by cranial bones

- The spinal cord is totally exposed