Development of the Nervous System

Question 1

The process of ___1.___ begins with the cells in the center of the ___2.___ becoming wedge-shaped as a result of ___3.___ , defining a median ___4.___ at which the neural plate bends

Answer 1

1. neurulation
2. neural plate
3. apical constriction
4. “hinge point”

Question 2

The neural folds are brought together by process of ___1.___ (reduces the width of the neural plate and also elongates the forming ___2.___ along the ___3.___ axis)

Answer 2

1. convergent extension
2. neural tube
3. antero-posterior

Question 3

Additional ___1.___ “hinge points” with ___2.___ cells also form on the sides of the ___3.___

Answer 3

1. dorso-lateral
2. wedge-shaped
3. neural groove

Question 4

Apical constriction in the cells is due to ___1.___ contraction

Answer 4

1. actomyosin

Question 5

The cells at the tips of the folds develop ___1.___ and ___2.___ that ___3.___ when the folds meet ( ___4.___ )

Answer 5

1. lamellipodia
2. filopodia
3. interdigitate
4. neural tube closure

Question 6

The neural tube, which is initially part of the ___1.___ , separates from the ___2.___ after its formation as a result of changes in ___3.___

Answer 6

1. ectoderm
2. presumptive epidermis
3. cell adhesiveness

Question 7

Because the closing of the ___1.___ is a complex process and it is perhaps not surprising that the process goes wrong relatively ___2.___ (neural tube defects NTDs)

Answer 7

1. neural tube

2. frequently

Question 8

T or F: NTDs are among the most common human birth defects ( ___1.___ births), and in their most severe forms are lethal, resulting in stillbirth or death within a few days

Answer 8

TRUE

1. 1:1500

Question 9

At the time of closure of the ___1.___ , neural crest cells can be seen as emerging loose ___2.___ on each side of the ___3.___ ( ___4.___ )

Answer 9

1. neural tube
2. mesenchyme
3. midline
4. epithelial-to-mesenchymal transition

Question 10

The individual neural cells then migrate away from the neural tube on both sides under the guidance of ___1.___

Answer 10

1. chemical cues

Question 11

Neural crest cell migration is guided by signals from other cells and by interactions with the ___1.___

Answer 11

1. extracellular matrix

Question 12

In neural crest cells migrating in the trunk, repulsive interactions between ___1.___ in the posterior halves of the somites and ___2.___ on the neural crest cells prevent their migration through the ___3.___

Answer 12

1. ephrins
2. eph receptors
3. posterior halves