2 Development and Anomalies of development of the CNS

Question 1

By which point are the first neurones formed?

Answer 1

22-26 days (prenatal)

Question 2

By which point is neurone proliferation mostly complete?

Answer 2

12 months postnatal

Question 3

Until what age are synapses continuing to be laid down?

Answer 3

3 years

Question 4

From which embryonic structure does the nervous system and skin arise from?

Answer 4

ectoderm

Question 5

When does neuralation occur?

Answer 5

3 weeks post conception

Question 6

What allows the neural plate to form over the notochord?

Answer 6

cell-cell interactions (mesoderm + notochord, cell surface)

extracellularly secreted molecules

Question 7

What does the neural screst go on to form?

Answer 7

any neurone with a cell body in the peripheral nervous system (sensory neurones, postganglionic ANS neurones)

all of the myelination cells (Schwann cells)

Question 8

What might cause defective closure of the neural tube?

Answer 8

massive cell division (folic acid)

gene defects

Question 9

What might an anterior neural tube defect cause?

Answer 9

anencephaly

Question 10

What might a posterior neural tube defect cause?

Answer 10

spina bifida

Question 11

What are the 3 main vesicles of the anterior end of the developing brain?

Answer 11

forebrain
midbrain
hindbrain

Question 12

What are the axis for neurone location?

Answer 12

anterior - posterior
dorsal - ventral
medial - lateral

Question 13

What are some signs for polarity in anterior-posterior patterning?

Answer 13

Dickkopf and noggin (anteriorising)

Question 14

What vitamin might you not want to give to a pregnant woman?

Answer 14

Vitamin A

Question 15

What is Shh and what is it associated with?

Answer 15

Sonic Hedgehog

ventral expression

Question 16

What does Shh control?

Answer 16

ventral expression of:

motor neurones of CN
dopaminergic neurones
serotonergic neurones

Question 17

The loss of what type of neurone is associated with Parkinson’s disease?

Answer 17

dopaminergic neurones

Question 18

What are the 3 stages to cortical layering?

Answer 18

proliferation
migration
differentiation

Question 19

Where do neurones proliferate?

Answer 19

ventricular zone

Question 20

How long does the proliferation stage of cortical layering take?

Answer 20

cortical neuroblasts are born in weeks 5-20

250 000/min

Question 21

What pathology is associated with a proliferation defect in cortical layers?

Answer 21

microencephaly in Zika virus

Question 22

What acts as a scaffolding in migration in cortical layering?

Answer 22

radial glia

Question 23

Where to post-mitotic immature neurones originate from?

Answer 23

ventricular zone (where the proliferating cells are)

Question 24

What types of pathology are associated with migration in cortical layering?

Answer 24

cortical dysgenesis (particularly Lissencephaly)

Question 25

What are the 2 main cortical features of Lissencephaly?

Answer 25

Smooth cortex

disorganised layers

Question 26

What key phenotypic features does differentiation dictate?

Answer 26

neurotransmitters
receptors
ion channels

Question 27

What 2 things do axons need to do when growing?

Answer 27

grow towards correct targets

fasculation

Question 28

How do axons grow towards correct targets?

Answer 28

growth cones are sensitive to chemoattactants and repellants

Question 29

Name 2 examples of chemo attractants / repellents

Answer 29

netrin

ephrin

Question 30

What facilitates fasciculation?

Answer 30

Cell Adhesion Molecules

Question 31

What facilitates synaptogenesis?

Answer 31

Neutrophic factors like NGF

Question 32

What process regulates synaptogenesis?

Answer 32

refinement by apoptosis

Question 33

When might refinement be pathological?

Answer 33

Alzheimer’s

Parkinson’s