Development Of The Ns 2

Front 1

What is the Retina?

Back 1

A specialized organ of the CNS

Front 2

What does the Retina develop from?

Back 2

An outpocketing of the diencephalon

Front 3

What reciprocal interactions give rise to the eye development?

Back 3

-Lens placode
-Optic vesicle

Front 4

What is a Placode by definition?

Back 4

A region of ectoderm that has regional identity - for instance the Lens placode, Otic placode, etc.

Front 5

What is the Optic vesicle derived from?

Back 5

Neural ectoderm

Front 6

What is the lens placode derived from?

Back 6

Surface ectoderm

Front 7

How does the retina develop morphogenically?

Back 7

By first the outpocketing, then an invagination.

Front 8

What does the lens placode give rise to?

Back 8

-Lens vesicle

Front 9

What does the lens vesicle give rise to?

Back 9

The lens

Front 10

How do the layers of the developing retina differ from that of the cortex?

Back 10

The ventricular (germinative) layer is NOT on the lumen side - a result of the weird morphogenesis.

Front 11

What is similar about retinal neuroepithelial migration compared to cortical?

Back 11

They both undergo interkinetic nuclear migration.

Front 12

What type of cell capacity do neuroepithelial cells have?

Back 12

Multipotent

Front 13

What are the 2 layers of the Optic cup; what do they become?

Back 13

1. Outer layer: pigmented epithelium
2. Inner layer: ventricular, intermediate, and marginal zones.

Front 14

In what direction does cell proliferation and migration occur in the retina?

Back 14

From Apical (back) to Lumenal (front) instead of the normal lumen->outside - because the ventricular zone is located away from the lumen.

Front 15

What are the retinal precursor cells?

Back 15

Multipotent neuroepithelium

Front 16

How does neuroblast migration in the retina compare to cerebral and cerebellar cortex?

Back 16

Both exhibit RADIAL migration but retinal migration is not guided by glial cells b/c they haven't developed yet.

Front 17

Where do the first cells to become post-mitotic in the ventricular zone move?

Back 17

To the basal-most layer.

Front 18

What is the arrangement of the final layers of the retina?

Back 18

Jumbled up - less stereotyped birth order.

Front 19

What is important to remember about the retinal precursor cells? In Cerebellar?

Back 19

Retinal: They are multipotent
Cerebellum: they are totipotent

Front 20

What 2 cell types contribute to retinal development again?

Back 20

1. Neural crest (moved away from neural tube)
2. Neuroepithelium (real stuff)

Front 21

What contributes to the peripheral nervous system?

Back 21

Same stuff:
-Neural crest
-Cranial Placodes

Front 22

What are the 4 important features of the neural crest contributing to the PNS?

Back 22

1. Have anterior to posterior specializations
2. There is a relationship between their time of migration and the type of derivative that will develop
3. They are stem cells
4. Migratory routes convey information about their fates

Front 23

What exactly are neural crest cells?

Back 23

Totipotent cells that delaminate from the neural tube and migrate away to form other structures.

Front 24

What do neural crest cells have the capacity to do?

Back 24

Be reimplanted in the neural tube and still form CNS structures

Front 25

What 3 cell types do the neuroepithelial cells have the capacity to become?

Back 25

1. Epithelial cells
2. Neural tube cells
3. Neural crest cells

Front 26

What does it mean to say the peripheral nervous system has ant/post patterning?

Back 26

Anterior develops first, then posterior.

Front 27

What type of cell are neural crest cells?

Back 27

Totipotent - really good examples of stem cells because they become so many various things.

Front 28

Where do neural crest cells go when they delaminate and migrate away from the neural tube?

Back 28

-Under scleratome
OR
-Over myotome
IN A STEREOTYPICAL PATTERN

Front 29

In what order do neural crest cells mature?

Back 29

Anterior first
Posterior last

Front 30

At what area of the neural tube do crest cells delaminate?

Back 30

The hinge region - these are multipotent cells; regionally fate, but if transplanted back into the CNS they would develop into neural cells.

Front 31

Is it important whether neural crest cells migrate OVER or UNDER the myotome?

Back 31

YES - the path of migration is very important in determining cell fate.

Front 32

What is Slug?

Back 32

A transcription factor that is expressed in an anterior to posterior fashion showing that's how neural crest cells mature.

Front 33

Where would you find more fated cells, vs. higher potential cells in developing neural crest?

Back 33

More fated: anterior

More capacity: posterior

Front 34

What happens to neuroepithelial cells as they become neural crest?

Back 34

Epithelial to mesenchymal transformation.

Front 35

What are the 2 migratory pathways that Neural Crest cells can follow?

Back 35

1. Dorsalateral
2. Ventromedial
-This is in reference to the myotomes

Front 36

What do cells that follow the Dorsalateral pathway give rise to?

Back 36

Ectodermal pigment cells

Front 37

What do cells that follow the ventromedial pathway give rise to?

Back 37

-Dorsal root ganglia
-Sympathetic chain ganglia
-Dorsal aorta

Front 38

Where do neural crest cells migrate along somites?

Back 38

ONLY ROSTRAL TO THEM!! NOT CAUDAL.

Front 39

What are Ephrins?

Back 39

A family of guiding cepps - receptors and ligands that set up signaling cascades between somites and neural crest cells.

Front 40

What is responsible for neural crest cells avoiding the caudal domain of somites?

Back 40

Ephrin A4 receptor

Front 41

How can neural crest be classified based on its Anterior-Posterior migration?

Back 41

-Cranial
-Vagal
-Trunk
-Lumbosacral

Front 42

What is the importance of the A-P migratory positions of neural crest cells?

Back 42

It determines the type of derivative that those cells will become.

Front 43

5 Derivatives of Cranial neural crest cells:

Back 43

-Neurons
-Glia
-Smooth muscle
-Cartilage
-Melanocytes

Front 44

Derivative of Vagal/Lumbosacral neural crest cells:

Back 44

Enteric nervous system

Front 45

4 Derivatives of Trunk neural crest cells:

Back 45

-Neurons
-Glia
-Adrenochromaffin cells
-Melanocytes

Front 46

What is the definition of a stem cell?

Back 46

A cell that can give rise to an identical daughter stem cell (self-renew) or to one or more types of differentiated cells.

Front 47

What is a pluripotent stem cell?

Back 47

One that can give rise to TWO or more types of differentiated cells.

Front 48

What is a placode?

Back 48

An epidermal thickening that gives rise to specialized nervous system structures.

Front 49

What are the placodes that develop? (5)

Back 49

-Olfactory
-Lens
-Otic
-Trigeminal
-Epibrachial

Front 50

What is Hirschprung disease?

Back 50

An enteric nervous system disease that is caused by defects in RET signaling.

Front 51

What is RET?

Back 51

A transmembrane receptor that binds RET ligands and is a Tyrosine Kinase signalling transducer.

Front 52

How does variability in the degrees of patients suffering from Hirschprungs Disease arise?

Back 52

From the complexity of the RET signalling pathway - different mutations can be classified.

Front 53

What class of mutations is more severe?

Back 53

Class 1 more severe than Class IV.