L16-17: Nervous System Development

Question 1

the neural tube divides into ?

Answer 1

prosencephalon
mesencephalon
rhombencephalon
spinal cord

Question 2

list the pentapartite brain

Answer 2

pro into 2
1. telencephalon
2. diencephalon
3. mesencephalon
rhom into 2
4. metencephalon
5. myelencephalon

Question 3

derivates of telencephalon

Answer 3

paleocortex
corpus striatum
neocortex

Question 4

derivates of diencephalon

Answer 4

epithalamus
thalamus
hypothalamus
infundibulum

Question 5

derivates of mesencephalon

Answer 5

tectum
tegmentum
cerebral peduncles

Question 6

derivates of metencephalon

Answer 6

cerebellum

pons

Question 7

derivates of myelencephalon

Answer 7

medulla

Question 8

neural tube wall development

Answer 8

1. early neuro epithelium
   - –simple cuboidal
2. neural plate
   - –simple columnar
3. early neural tube wall
   - –pseudostratified
   * *external limiting memb = basal lamina
4. late neural tube wall
   - –stratified epi

Question 9

proliferation w/in the neural tube

Answer 9

mitosis occurs close to lumen

DNA replication occurs close to external limiting memb

(talking pseudostratified cells here)

Question 10

if metaphase plate is perpendicular aka next to lumen, what will result ?

Answer 10

2 daughter cells will remain proliferative

Question 11

if metaphase plate is parallel to inner margin, what will result ?

Answer 11

daughter close to lumen = remains proliferative

farther cell = express notch receptor

• -become postmitotic
• -move to ext limit memb
• -become neuroblast = pre-neuron

Question 12

in the developing central nervous system, when do most cell lineages lose their mitotic capabilities ?

Answer 12

the cell lineage stage right before their final form

except for the neuron line

Question 13

ventral signaling

Answer 13

notochord uses Shh

to induce formation of floor plate of neural tube

Question 14

when Shh is produced by the floor plate, this induces ?

Answer 14

formation of motor neurons

Question 15

dorsal signaling - dorsalizing effect

Answer 15

ectoderm flanking the neural plate uses BMP

• -to induce snail-2 in future neural crest
• -and later to maintain pax3 and pax7

to create dorsalizing effect

Question 16

dorsal signaling - suppressing dorsalizing effect

Answer 16

floor plate uses Shh
–to suppress expression of Pax3 and Pax7

to suppress dorsalizing effect in the basal plate

Question 17

isthmic organizer location

Answer 17

between mesencephalon and the metencephalon

Question 18

the isthmic organizer is a signaling center for ?

Answer 18

main signal = FGF-8

organizes and polarizes dorsal midbrain and cerebellum

Question 19

isthmic organizer signaling

Answer 19

FGF-8 & Wnt-1 induce expression of:
—En1, En2, Pax2, Pax5

the conc of these gene products decreases away from the isthmic organizer

Question 20

dorsoventral patterning of midbrain is primarily due to _____ located ______ .

Answer 20

Shh

ventrally

Question 21

in the midbrain dorsoventral axis, Shh restricts the expression of ?

Answer 21

Pax7

and similar molecules

Question 22

Pax-7

Answer 22

related to formation of alar plate

Question 23

Pax-6

Answer 23

expressed in alar plate of diencephalon

master gene of eye formation

Question 24

Pax-6 and En-1 relationship

Answer 24

inhibit each other

this reciprocal inhibition results in formation of diencephalic-mesencephalic border

Question 25

forebrain segmentation is represented by ?

Answer 25

set of 3 prosomeres P1-3 mostly shh signaling some Wnt-1

Question 26

P1-P3

Answer 26

define the diencephalon

Question 27

P2-P3

Answer 27

define dorsal and ventral thalamus

Question 28

basal plate of secondary rhombencephalon develops into ?

Answer 28

hypothalamus

Question 29

alar plate of the secondary rhombencephalon develops into ?

Answer 29

cerebral cortex basal nuclei optic vesicles

Question 30

motor axon outgrowth

Answer 30

axons grow out from the motor neuroblasts located in the basal plate of the spinal cord

Question 31

what maintains separation between CNS and PNS components?

Answer 31

boundary caps created by neural crest cells

Question 32

formation of a sensory neuron

Answer 32

cells bodies - -from neural crest cells - -form sensory spinal ganglia axons --grow from these bodies toward spinal cord and periphery boundary caps maintain separation here too

Question 33

sympathetic preganglionic motor neurons arise ?

Answer 33

from intermediate/lateral horns of gray matter levels of origin T1-L2

Question 34

autonomic ganglia are derived from ?

Answer 34

neural crest cells

Question 35

sympathetic preganglionic motor neurons -- myelinated axons

Answer 35

move thru ventral roots of the spinal cord then thru the white communicating rami

Question 36

sympathetic preganglionic axons synapse with ?

Answer 36

cell bodies of postsynaptic sympathetic motor neurons w/in the ganglia

Question 37

options for sympathetic preganglionic fibers ?

Answer 37

1. ascend or descend w/in sympathetic chain and synapse w/ postganglionic neurons 2. synapse immediately w/ postganglionic neurons 3. pass to periphery collateral ganglia to synapse w/ postganglionic neurons 1. ascend/descend 2. synapse where u r 3. to collateral

Question 38

sympathetic postganglionic motor neurons

Answer 38

not myelinated may extend from collateral ganglia to target organs may reenter ventral root of spinal nerve thru gray ramus communicans

Question 39

what determines differentiation of autonomic neurons?

Answer 39

BMPs | determine whether migrating neural crest cells dif into autonomic neurons or other derivatives

Question 40

select the type of NT used for sympathetic vs parasympathetic cells

Answer 40

sym = adrenergic para = cholinergic

Question 41

what is the role of radial glial cells in the building of a cortex?

Answer 41

migrating bipolar neurons use their long process as a guiding mechanism to reach the surface where they can begin to layer the cortex

Question 42

characteristics of radial glial cells

Answer 42

located in ventricular zone each one extends a long process - -which passes thru intermediate zone, cortical plate, marginal zone - -to the surface of the brain

Question 43

the topographical arrangement of the myelencephalon is almost identical to the ______ . what is the major difference?

Answer 43

spinal cord pronounced expansion of the roof plate to form the thin roof over the 4th ventricle

Question 44

expression of what gene set is responsible for the differentiation of specific nuclei in the myelencephalon?

Answer 44

hox genes

Question 45

Krox 20 segmentation gene

Answer 45

involved in formation of rhombomeres 3 and 5

Question 46

what are the major derivative of the metencephalon ?

Answer 46

pons - basal plate | cerebellum - alar plate

Question 47

the cerebellum forms in the region of ?

Answer 47

the rhombic lips | rhombomeres 1-8

Question 48

the rhombic lips are a product of ?

Answer 48

inductive interaction of roof plate and neural tube via BMP signaling

Question 49

cells that form the cortex in the cerebellar primordium

Answer 49

granule cells | purkinje cells

Question 50

granule cells migrate ?

Answer 50

1. migrate ant along dorsal region of rhombomere 1 | 2. migrate interiorly thru purkinje layer

Question 51

purkinje cells migrate ?

Answer 51

radially thru granule cells

Question 52

what are the superior cerebellar peduncles ?

Answer 52

massive fiber bundles between the cerebellum and the mesencephalon

Question 53

what are the major derivatives of the alar plates of the mesencephalon ?

Answer 53

tectum -- sup/inf colliculi

Question 54

where is Otx-2 located and how does it relate to shh?

Answer 54

it confines shh to the basal part of the midbrain

Question 55

where do the cerebral peduncles form ?

Answer 55

ventrolateral region of mesencephalon

Question 56

what is the function of cerebral peduncles ?

Answer 56

carry fibers between cerebral hemispheres and spinal cord

Question 57

what are the major derivatives of the diencephalon?

Answer 57

epi/hyp - thalamus

Question 58

what are the 3 patterning centers in the forebrain ?

Answer 58

1. rostral patterning center 2. dorsal patterning center 3. ventral pc

Question 59

rostral pc

Answer 59

FGF-8

Question 60

dorsal pc

Answer 60

BMPs and Wnts

Question 61

ventral pc

Answer 61

shh

Question 62

spina bifida

Answer 62

forms of this depend on meninge position