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Embryology Exam III > Neural Crest > Flashcards

Flashcards in Neural Crest Deck (34)
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1

What induces neural crest into non-neuronal ectoderm?

-BMPs and Wnts

-inhibitory actions of noggin and chordin

2

What induces neural crest from mesoderm?

-FGF-8

3

While in the neural tube, neural crest cells are what? What helps form tight junctions?

-epithelial

-cadherins and other CAMs are important in forming tight junctions

4

What are the factors involved in neural crest breaking free?

-CAMs are lost and remain downregulated during migration but may be reexpressed at the end of migration

-Snail -1, Snail-2, and Foxd3 are important in allowing cells to break free

5

What are the three migratory pathways of neural crest migration?

-ventral/sympathoadrenal path: first emigrating cells

-ventrolateral path: second wave of emigrating cells

-dorsolateral path: last wave of emigrating cells

6

What are the migratory neural crest substrates? Ligand/receptors?

-basal lamina is preferable

-extracellular matrix components
+fibronectin
+laminin
+type IV collagen

-ligand/receptor pair guidance molecules
+Robo/Slit
+neuropilin/semaphorin
+ephrin/eph

7

Early migratory neural crest cells:

-have most potential for differentiation

8

Later migratory neural crest cells:

-can only differentiate into cells characteristic of more dorsal locations
+spinal ganglia

9

Late migratory neural crest cells:

-can only form melanoblasts

10

What are the neural crest cell divisions?

-trunk neural crest
+sympathoadrenal lineage
+sensory lineage
+melanocyte lineage

-cranial neural crest

-circumpharyngeal neural crest

-cardiac neural crest

-vagal crest

11

Neural crest pathways extend from where?

-somite 6 caudally

12

Outline the sympathoadrenal pathway.

-follows intersomitic blood vessels around and between somites

13

Outline the ventrolateral pathway.

-neural crest cells enter and pass through anterior sclerotome compartments
+repulsed from posterior compartment by interaction of semaphorinA3F and neuropilin-2

+passage is facilitated via thrombospondin

14

Outline the dorsolateral pathway.

-migrate just beneath ectoderm

15

What happens to neural crest cells that take the sympathoadrenal lineage?

-gives rise to:
+adrenal chromatin cells

+adrenergic sympathetic neurons

+cholinergic sympathetic neurons

16

What happens to neural crest from the sensory/ventrolateral lineage?

-dorsal root ganglia

-Schwann cells

17

What happens to neural crest from the melanocyte/dorsolateral lineage?

-melanocytes

18

Cranial neural crest are thought to have been involved in evolution of what? Where do they arise from?

Vertebrate head

-cells arise from region of prosomere 1-3 and migrate as a continuous sheet over much of the head

19

What inhibits neural crest cells from arising anterior to diencephalon?

-Dickkopf-1

20

Cells arising from diencephalon posteriorly through R3 do not express what?

-Hox genes

21

Cells from R4 and posteriorly DO express what?

-Hox genes

22

Neural crest cells from R1-R2 -> pharyngeal arch 1

- does not require Hox influence

23

Neural crest cells from R4 -> pharyngeal arch 2

-requires Hoxa2 to keep it from becoming first arch

24

Neural crest cells from R6-R7 -> pharyngeal arch 3

-requires Hox3

25

Where does circumpharyngeal neural crest arise from?

-areas of somites 1-7

26

What does the circumpharyngeal ridge do?

-arc shaped aggregation of cells passing behind 6th arch

-cells migrate centrally and then cranially to provide pathways for CN XII and related musculature

-most neural crest cells from somites 1-3 -> pass into pharyngeal arches 4 and 6 or form cardiac crest

-neural crest cells from R4-7 -> make up vagal crest and form parasympathetic innervation for digestive tract

27

Where does cardiac neural crest arise from?

-somites 1-3

28

Cardiac neural crest migrate toward the heart and give rise to what?

-septa that divide conus arteriosus into aortic and pulmonary arteries

-leaflets of semilunar valves

-thymus, thyroid, parathyroid glands

29

Where does vagal neural crest come from?

-arises from circumpharyngeal crest and exit from levels of somites 1-7

30

What is vagal neural crest associated with?

-gut enteric system (parasympathetic)

-dorsal root ganglia

-few sympathetic ganglia