W19-L6: Development of the CNS Flashcards Preview

Matt's Block 06 - Neuro block > W19-L6: Development of the CNS > Flashcards

Flashcards in W19-L6: Development of the CNS Deck (21):
1

In what direction does the neural tube develop

Rostral to caudal

2

How many events of neural fold closure are there and which one does folate protect against?

5, each which can independently go wrong. Folate protects against stage 5 which is called spina bifida

3

Segmentation of neural tube

Rostral end of neural tube starts to swell and forms 3 distinct vesicles:
• Prosencephalon (forebrain)
• Mesencephalon (midbrain)
• Rhombencephalon (hindbrain)

4

Further segmentation of neural tube after 3 swellings

Prosencephalon splits - telencephalon and diencephalon
• Rombencelphalon – 7 segments

5

Neural crest cells

Cells at top of the neural tube form the neural crest, which migrate away from the neural tube to form a wide range of structures

6

Neural crest derivatives

Peripheral nervous system, melanocytes, Muscle cartilage and bone of skull, jaws, face
and pharynx, dentine

7

Neural crest migration

Neural crest cells follow specific paths through the embryo

8

Ventricular Zone

All neurones are born at ventricular surface (which contains stem cells) and then migrate to outer surface to add layers

9

What is the role of radial glia?

Neurones use radial glial cells as scaffolding to migrate across the cortex

10

Developmental disorders can be caused by

Cortex can be malformed as a result of mutations in genes that affect migration

11

Reelin mutation

Decreased folds and white matter due to poor migration of new neurones

12

Lissencephaly

Smooth brain due to smaller number of cells because of mutations in neuronal migration

13

Floor plate development

Sonic Hedgehog is released from notochord which causes the closest cells to form a floor plate which gives the direction of ventral

14

Role of the floor plate

Induces ventral horn motor neurones by releasing sonic hedgehog

15

Induction of interneurones

Ventral horn Motor neurones can tell interneurones they are more dorsal and they form interneurones (due to motor neurone factor)

16

What is the importance of the initial scaffold of axon tracts laid down by pioneer axons?

Guides all the other axons later on

17

Growth cone

A dynamic structure of cytoskeleton that is capable of crawling across a surface and pulls the axon into position

18

Axon navigation

Growth cone responds to local cues and grows up chemical gradients

19

What is the "critical period" in CNS development?

Refinement of synaptic connections that establishes mature functional nervous system

20

If you temporarily cover one eye shortly after birth in a kitten, then test covered eye six months later...

the eye is blind as the visual cortex has been remodelled. 2-3 weeks after birth closing the eye has less of an effect and at 6 weeks no effect

21

If you temporarily cover both eyes shortly after birth in a kitten, then test covered eyes six months later...

They are normal as refining connections depending on experience, if no information from one eye will choose the other, if both are covered has no information from either so cannot choose one over the other i.e no ocular dominance

Decks in Matt's Block 06 - Neuro block Class (48):