Lecture 19

Question 1

neural crest cells originate from the lateral margins of the what?

Answer 1

neural plate

Question 2

the induction of neural crest tissue from the non-neural ectoderm uses what genes?

Answer 2

BMPs and Wnts

Question 3

induction of neural crest tissue from mesoderm involves what gene?

Answer 3

FGF-8

Question 4

what 3 genes are important in allowing cells to break free?

Answer 4

Snail-1, snail-2 and Foxd3

Question 5

in neural crest cell migration, the ventral/sympathoadrenal pathway has what wave of emigrating cells?

Answer 5

first wave

Question 6

in neural crest cell migration, the ventrolateral pathway has what wave of emigrating cells?

Answer 6

second wave

Question 7

in neural crest cell migration, the dorsolateral pathway has what wave of emigrating cells?

Answer 7

last wave of cells

Question 8

early migratory neural cells have most potential for differentiation. later cells have more dorsal locations. the latest cels can only form what?

Answer 8

melanoblasts

Question 9

neural crest cells divide into 5 different crests

Answer 9

trunk, cranial, circumpharyngeal, cardiac and vagal

Question 10

the trunk neural crest contains 3 migration pathways

Answer 10

sympathoadrenal, ventrolateral, dorsolateral

Question 11

trunk neural crest contains 3 lineages

Answer 11

sympathoadrenal, sensory and melanocyte

Question 12

the cranial neural crest is thought to have been involved in the evolution of what?

Answer 12

vertebrate head

Question 13

neural crest cells from R1-R2 give rise to pharyngeal arch 1 and do not require what genes

Answer 13

Hox

Question 14

neural crest cells from R14 give rise to pharyngeal arch 2 and requires what gene

Answer 14

Hoxa2

Question 15

neural crest cells from R6-R7 give rise to pharyngeal arch 3 and requires what gene

Answer 15

Hox3

Question 16

circumpharyngeal neural crest arises from area of what somites

Answer 16

1-7

Question 17

most neural crest cells from somites level 1-3 pass into the pharyngeal arches 4 and 6 and form the

Answer 17

cardiac crest

Question 18

neural cells from somite levels 1-3 and 4-7 make up the

Answer 18

vagal crest

Question 19

this gene prevents neurons from crossing the midline of the central nervous system

Answer 19

Slit-2

Question 20

this gene works to avoid cells the express slit-2. vagal crest cells do not express this and are able to cross the gut wall.

Answer 20

Robo (slit receptor)

Question 21

this syndrome involves pax-3 mutations and involves white stripe in the hair, deafness, cleft palate ect.

Answer 21

waardenburgs

Question 22

this condition is characterized by a deficiency in migration of neural crest cells into pharyngeal arches, mesoderm formation

Answer 22

charge

Question 23

this neurocristopoathy is due to a deletion in chr 22, and is related to defects in neural crest associated with 3rd and 4th pharyngeal arches, also called Q22

Answer 23

DiGeorge syndrome

Question 24

local thickening in embryonic ectodermal layer that generally makes up a group of cells in which an organ or ganglion will form

Answer 24

ectodermal placodes

Question 25

there are 6 major ectodermal placodes

Answer 25

hypophyseal, olfactory, lens, trigeminal, otic, and epibranchial

Question 26

the initial expression of this gene is in the lens, nasal placodes and diencephalon. absence of this gene results in early optic vesicle formation, but the rest of the eye does not develop.

Answer 26

Pax6

Question 27

low concentrations of Shh in distal optic stalk permits expression of Pax6 and development of optic vesicle, this will lead to the formation of what?

Answer 27

retina

Question 28

high concentrations of Shh in the proximal optic stalk decreases the expression of Pax6 and induces the expression of what?

Answer 28

Pax2

Question 29

what gene is necessary for corneal induction?

Answer 29

Pax6

Question 30

what gene is necessary for the differentiation of the pigmented retina and is stimulated by Shh?

Answer 30

Otx2

Question 31

the nasotemporal (a/p) axis is fixed first and established in part by what gradients?

Answer 31

ephrins and receptors

Question 32

the dorsoventral axis is fixed second and is established by what gradients?

Answer 32

by the antagonist actions of Shh, BMP, ventropin, Tbx5, Pax2, Vax2