early development of nervous system

Question 1

which “state” do BMPs push ectoderm towards?

Answer 1

the epidermal state

Question 2

where are BMP inhibitors produced?

Answer 2

in the notochord

Question 3

blocking BMP leads to what?

Answer 3

induces the cells to take on a neural fate (default pathway)

Question 4

what is characteristic at 20 days?

Answer 4

neural tube formation

Question 5

in which directions does the neural tube close?

Answer 5

from the mid line both anteriorly & posteriorly

Question 6

what disorder does this statement describe?

“failure of the posterior end of the neural tube to close”

Answer 6

spina bifida

Question 7

what disorder does this statement describe?

“failure of the anterior end of the neural tube to close”

Answer 7

anencephaly & holoprosenchephaly

Question 8

what are the 4 things that the neural crest gives rise to?

Answer 8

1. cranial neural crest
2. trunk neural crest
3. vagal & sacral neural crest
4. cardiac neural crest

Question 9

what does “patterning” do?

Answer 9

makes cells in one area different from cells in another area

Question 10

what does sonic hedgehog secrete?

Answer 10

ventral signal motor

Question 11

what does TGF betas secrete?

Answer 11

dorsal signal sensory

Question 12

what can high or low Shh expression lead to?

Answer 12

dorsal-ventral polarity

Question 13

what 4 things does Anterior/posterior patterning lead to?

Answer 13

1. spinal cord
2. rhombencephalon
   
   • metencephalon: future pons
   • myelencephalon: future medulla
3. mesencephalon: future midbrain
4. prosencephalon
   
   • diencephalon: future thalamus & retina
   • telencephalon: future forebrain

Question 14

what is the role of HOX genes in the posterior CNS patterning?

Answer 14

involved in defining segmental differences in the spinal cord, medulla and pons

Question 15

how do HOX genes work to make unique segments in the CNS?

Answer 15

work through encoding transcriptional activator and repressors that will turn on/off genes to create unique patterns of gene expression

Question 16

anterior/posterior patterning in the CNS is largely accomplished by_______?

Answer 16

HOX genes

Question 17

what happens if you knockout OTX2?

Answer 17

complete loss of anterior polarity

these embryos completely lack forebrain neural structures

Question 18

where do neural cells proliferate & differentiate?

Answer 18

in the ventricular zone

Question 19

what is the ventricular zone?

Answer 19

thin strip of cells surrounding the CSF filled ventricles

Question 20

increasing the number of pluripotent neural stem cells does what to the ventricular zone thickness?lateral size?

Answer 20

the thickness stays relatively constant and the ventricular zone expands laterally

Question 21

if a pluripotent neural stem cell divides asymmetrically, what two cells is it giving rise to?

Answer 21

another NSC and 1 neural precursor

Question 22

in the cerebral cortex, which comes first; neurogenesis or gliogenesis?

Answer 22

neurogenesis comes first

Question 23

which two transcription factors regulate neural cell differentiation?

Answer 23

notch and bHLH

Question 24

which comes first; oligodenderogiosis or astrogliosis?

Answer 24

astrogliosis

Question 25

what inhibits astrogliogenesis differentiation? what activates it?

Answer 25

notch dependent activation and bHLH genes inhibit it

Question 26

in development, when is neurogenesis usually completed?

Answer 26

early in 2nd trimester

around week 19

Question 27

when is gliogenesis complete?

Answer 27

well after birth! there is no myelination at birth and it continues to increase to about 20 years old

Question 28

what does radial migration of neurons depend on?

Answer 28

radial glia

Question 29

what is a main function of the radial glial?

Answer 29

they give rise to neurons & provide scaffolding on which they can migrate to their appropriate destination

Question 30

describe what it means that the cortex forms in an inside to outside manner

Answer 30

the layers closest to the ventricular zone form first (early born) while the layers furthest away from the ventricular zone form last (layer born)

Question 31

what occurs in a reelin mutation?

Answer 31

disrupts the inside-out layering and leads to a cortex that is inside out