development of the CNS

Question 1

what is the wall of the neural tube called

Answer 1

neuroepithelium

Question 2

what does the neuroepithelium consist of (inside to outside)

Answer 2

endoderm, mesoderm, notochord medial, neural plate (most important), ectoderm

Question 3

what does the neural tube form

Answer 3

CNS

Question 4

what happens to the neural plate during early development of the neural tube

Answer 4

folds down towards the notochord, forming the neural canal (neural fold) - crucial for development

Question 5

what is the outcome of early development of the neural tube

Answer 5

endoderm, notochord, mesodermal somite, circular wall of neural tube (made of neuroepithelium - basis of CNS) with neural canal in the middle and neural crest just outside at top on either side of neural tube wall

Question 6

what does the neural crest form

Answer 6

PNS

Question 7

3 derivatives of neuroepithelium differentiation

Answer 7

neuroblasts (-blast = origin), glioblasts, ependymal cells

Question 8

what and where are neuroblasts

Answer 8

all neurones with cell bodies in CNS

Question 9

2 types of glioblasts

Answer 9

astrocytes (multi-functional; BBB), oligodendrocytes (myelinating cells)

Question 10

what do ependymal cells line

Answer 10

ventricles, central canal of spinal cord

Question 11

proliferation of neuroepithelium: cell structure at beginning

Answer 11

massive proliferation as actively dividing towards inside

Question 12

differentiation of neuroepithelium into CNS cells: structure from inside to outside

Answer 12

all cells in ependymal layer (ventricles on inside layer) -> some migrate into grey matter and divide into neuroblasts and others remain -> grey matter (somas) grows outwards to become white matter (myelinated axons in ascending and descending neurones)

Question 13

layers of neural tube (from inside to outside)

Answer 13

ependymal layer (germinal layer) lining canal -> grey matter (mantle layer) -> white matter (marginal layer); brain opposite: grey matter outside, white matter inside

Question 14

what lies at the a) ventral and b) dorsal section of the neural tube canal

Answer 14

a) floor plate, b) roof plate

Question 15

what lies outside of the white matter in the neural tube

Answer 15

neural crest (one on each side)

Question 16

what controls neural tube differentiation, where do they come from and what do they interact with

Answer 16

signalling molecules, sequentially secreted by surrounding tissues, interact with neuroblast receptors

Question 17

what do signalling molecules specifically control in neural tube differentiation, and how

Answer 17

control migration and axonal growth by attraction and repulsion

Question 18

what does the control of neural tube differentiation depend on

Answer 18

concentration gradient and timing of signalling molecules