Defects of Neural Developments

Question 1

neurulation=

Answer 1

the formation of the neural tube, driven by intrinsic and extrinsic factors

Question 2

neurulation begins

Answer 2

anteriorly, moves posteriorly

Question 3

secondary neurulation=

Answer 3

de novo formation of the lumen

Question 4

inititiation/neurulation of neural tube closure is best described as

Answer 4

discontinuous, as it is initiated in many areas which then merge

Question 5

craniorachischisis=

Answer 5

middle part of the brain doesn’t close up (affects closure 10

Question 6

ancephaly=

Answer 6

failure of neural closure in fore-mid-hind brain (affects closure 2)

Question 7

spina bifida=

Answer 7

at posterior neuropore, at transition betweem lumen and solid mass so becomes exposed (affects closure 3)

Question 8

the neural crest is a

Answer 8

transient and discrete embryonic population, natural stem cell pop.

Question 9

the neural crest generate

Answer 9

neurons and glia of the PNS, pigment skin cells, cartilage in the head, DRG

Question 10

describe the development of the DRG

Answer 10

develops from the neural crest, stops either side of the spinal cord and may require signals from the spinal cord.

Question 11

what are the 3 kinds of sensory nuclei in the DRG?

Answer 11

nociceptors (trka), mechano and proprio ceptors (trkb and c)

Question 12

TrkA=

Answer 12

receptor for neurotrophin (nerve growth factor)

Question 13

TrkB=

Answer 13

neurotrophic tyrosine kinase receptor

Question 14

TrkC=

Answer 14

NT-3 receptor

Question 15

what mutation underlies CIPA?

Answer 15

TrkA mutation

Question 16

CIPA-=

Answer 16

congenital insensitivity to pain with anhidrosis

Question 17

what sensory neurons are affective by CIPA (and hence TrkA receptors) ?

Answer 17

nociceptors

Question 18

what is neuroblastoma?

Answer 18

a tumour arising from the neural crest, of cells that will form the sympathetic nervous system

Question 19

enteric system=

Answer 19

intrinsic NS of GI tract, which is populated with neural crest cells, from vagal and sacral levels of the neural tube

Question 20

what does a mutation in Ret result in?

Answer 20

Hirschsprungs disease, which involves angliogenesis of the gut so no peristalsis

Question 21

what is Ret?

Answer 21

transmembrane receptor tyrosine kinase

Question 22

what happens in ret knockout mice?

Answer 22

lact enteric neurons, so no peristalsis and absence of myenterica and submucous plexuses

Question 23

what does the death of precursors in ret knockout mice suggest about ret signalling?

Answer 23

that ret signalling is required for survival and diff. of precursors

Question 24

what is the most common brain tumour in children?

Answer 24

medulloblasoma

Question 25

medulloblastoma can arise fom

Answer 25

neuroepithelium or external granular layer (and can be developed from mutations in key developmental genes)

Question 26

the external granular layer arises from

Answer 26

progenitor cells in the rhombic lip

Question 27

progenitors in the ventricular zone give rise to

Answer 27

purkinje cells

Question 28

what is the largest connective structur in the brain and how many axons does it have?

Answer 28

corpus callosum, 190 mill.

Question 29

how does the corpus callosum develop?

Answer 29

from pioneer axons and signals from midline glial structures which help funnel the pioneer axons through

Question 30

what is autism?

Answer 30

pervasive developmental disorder which affects language and social behaviour, there are a number of associated genes associated at synapses

Question 31

what does agenisis of the CC cause?

Answer 31

autism like symptoms

Question 32

what develpmental disorder does foetal alcohol syndrome have a 7% incidence of?

Answer 32

Ag CC

Question 33

what are andermann syndrome, XLAG, mowat wilson syndrome, HSAS/MSASA and donnai-barrow syndome associated with?

Answer 33

AgCC