Neural tube and crest

Question 1

Neurulation

Answer 1

Formation of the neural tube

Question 2

Primary neurulation

Answer 2

The process of the neural plate transforming into the neural tube

Question 3

Secondary neurulation

Answer 3

The process that forms the posterior portion of the neural tube by the coalescence of mesenchyme cells into a solid cord

Question 4

Junctional Neurulation

Answer 4

When primary and secondary neurulation meed and primary transitions to secondary

Question 5

What three ectodermal derivatives are produced by neurulation?

Answer 5

1. Surface ectoderm
2. Neural crest
3. Neural tube

Question 6

Medial Hinge Point

Answer 6

Cells at midline anchored to notochord
Forms by SHH

Question 7

Dorsal Lateral Hinge Point

Answer 7

Has apical constriction
Forms when Noggin inhibits BMP

Question 8

Notochord

Answer 8

Transient mesodermal rod that patterns nervous system
Signals SHH to activate MHP and inhibit Noggin

Question 9

Surface Ectoderm

Answer 9

BMP expressed, inhibits DLHP and MHP

Question 10

E-cadherin

Answer 10

Expressed in ectoderm

Question 11

N-cadherin

Answer 11

As neurulation begins, neural tissue is induced and expresses N-cad

Question 12

Filopodia

Answer 12

The tips of the neuro folds extend filopodia across the opening

Question 13

Environmental impact

Answer 13

Current hypothesis is that environmental factors can modify the epigenome, leading to transcriptional variation

Question 14

Folic Acid

Answer 14

Vitamin B9, Key facor in neural tube closure.

Question 15

Explain why there is great phenotypic variation in the class of human malformations known as neural tube defects

Answer 15

NTDs and multifactorial with more than 300 genes that could be effected

Question 16

Anencephaly

Answer 16

Failure to close the anterior of the neural tube forebrain (closure 2)
Skull vault doesn’t close

Question 17

Spina bifida

Answer 17

Failure of neural tube closure at closure 5

Question 18

Craniorachischisis

Answer 18

Usually miscarriage

Question 19

Neurocristopathies

Answer 19

Developmental disorders of neural crest cells.

Question 20

Neural crest cells

Answer 20

• vertebrates
• arise from dorsal neural tube
• give rise to multipotent progenitors
• Transient in early embryo

Question 21

NCC EMT

Answer 21

EMT is promoted by differential gene expression

Question 22

NCC specification

Answer 22

Medium Wnt and low BMP signaling in the gradient specify cell fate

Question 23

NCC Snail

Answer 23

Snail represses Sox2, and N-cad at the top of the cell. Snail also inhibits Cad-6B from being expressed outside of the top of the tube

Question 24

NCC Cad-6b

Answer 24

aids wnt and BMP to determine pre migratory NCCs

Question 25

Contact inhibion

Answer 25

Sends NCCs off laterally

Question 26

Neural crest “highways”

Answer 26

Environmental cues that send NCCs to their target tissues

Question 27

Cranial NCCs

Answer 27

Neck and cranial nerves, jaw bone, face cartilage

Question 28

Trunk NCC

Answer 28

Glial cells and melanocytes
Ganglia travel ventrally and transmit touch/pain to the spinal chord
Melanocytes travel dorsolaterally and create pigment cells

Question 29

Cardiac NCCs

Answer 29

Creates the septum that separates the pulmonary artery and the aorta

Question 30

Vagal/Sacral NCCS

Answer 30

Migrate and populate the gut
Enteric nervous system
-GDNF is released by developing gut
-GDNF + GRFa bind to Ret on NCCs
- migration to gut

Question 31

Somite

Answer 31

Mesodermal segments of vertebrate embryos that become the vertebral column

Question 32

Hirschprung’s Disease

Answer 32

the nerves in the large intestine don’t form properly

Question 33

How Eph/Ephrin guide NCC migration

Answer 33

NCCs migrate ventrolaterally through the anterior half of the somite
-ephrin is present posteriorly
-Ephrin ligands in the posterior connect with the Eph receptor in the NCC membrane and cause a repulsive interaction