Chapter 13

Question 1

What are the 3 different major cell lineages that the ectoderm forms?

Answer 1

1) Surface ectoderm
2) neural crest
3) Neural tube

Question 2

What does the surface ectoderm form?

Answer 2

primary epidermis

Question 3

What does the neural crest form? (4)

Answer 3

1) Peripheral neurons
2) neural support cells
3) pigmentation cells
4) dentine (of teeth)

Question 4

What does the neural tube form?

Answer 4

brain (anterior) and spinal chord (posterior)

Question 5

_______: the differentiation of the ectoderm into neural tissues and structures

Answer 5

neurulation

Question 6

_______: region of specified ectoderm that will take on new features

Answer 6

neural ectoderm

Question 7

Folding of the neural plate forms the _______ which is the beginning of the nervous system

Answer 7

neural tube

Question 8

When the embryo has the neural tube it is called a _______

Answer 8

neurula

Question 9

Cells involved in neurulation are called _______

Answer 9

neuroblasts

Question 10

_______: surrounding cells direct the neural plate to invaginate and pinch off from the remaining ectoderm as a hollow tube

Answer 10

primary neurulation

Question 11

_______: mesenchyme cells form a solid cord that then cavitates to form a hollow tube

Answer 11

secondary neurulation

Question 12

_______ mesenchyme cells are responsible for secondary neurulation

Answer 12

coalescing

Question 13

What are the 4 steps to 1° neurulation?
1) _______ of the neural plate
2) _______ of the neural plate
3) _______ of the plate into the neural groove
4) _______ of the neural groove and neural tube

Answer 13

1) formation
2) elongation
3) shaping
4) closure

Question 14

Formation of the neural tube:
- mesoderm signals overlying ectoderm to elongate into _______ neural plate cells

Answer 14

columnar

Question 15

Elongation of the neural plate:
- elongates in the _______ direction
- elongation driven by _______ preferentially aligned along the _______ axis extending the neural plate

Answer 15

anterior/posterior
cell divisions
A/P

Question 16

Shaping of the plate into the neural groove:
what are the two hinges formed during this step?

Answer 16

1) Medial hinge point (MHP)
2) Dorsolateral Hinge point (DLHPs)

Question 17

The medial hinge point forms in the center of the _______

Answer 17

neural plate

Question 18

The dorsolateral hinge points form at the connections between neural and the remaining ectodermal cells called the _______

Answer 18

neural folds

Question 19

Closure of the neural groove and neural tube:
cells change from _______ to _______ expression, and in many species, some of the cells at the junction migrate away as _______

Answer 19

E-cadherin to N-cadherin
neural crest cells
- mesenchymal cells that will form other tissues

Question 20

What are the names of the locations where the neural tube closes?

Answer 20

anterior neuropore
posterior neuropore

Question 21

_________: closure failure of the posterior end
- spinal cord open and can be corrected by in-utero surgery

Answer 21

spina bifida

Question 22

_______: closure failure at the anterior end
- brain/skull malformations, generally fatal

Answer 22

anencephaly

Question 23

Neural tube defects in 1 out of every_____ live human births
- mainly due to insufficient dietary _______

Answer 23

1000
folic acid (B9)

Question 24

Mutations in genes can lead to neural tube defects. What are some of these genes? (5)

Answer 24

1) Pax3
2) SHH
3) Grainy head
4) Fap2
5) open brain

Question 25

What environmental factors can lead to Neural tube defects?

Answer 25

deficiencies in: 1) cholesterol 2) zinc 3) folic acid Presence of: 1) diabetes 2) obesity

Question 26

While the posterior end of the tube is still forming, the anterior end begins to bulge and dramatically change in shape forming _________

Answer 26

3 primary vesicles

Question 27

By the time the posterior end closes, the _______ have begun to form

Answer 27

5 secondary vesicles

Question 28

(primary) _______: forms the cerebral hemispheres

Answer 28

Prosencephalon

Question 29

(primary) ________: neurons involved in motivation, movement, and depression

Answer 29

mesencephalon

Question 30

(primary) ________: cerebellum, pons, medulla oblongata - involved in involuntary breathing

Answer 30

Rhombencephalon

Question 31

________ divides the hindbrain into smaller compartments

Answer 31

rhombomeres

Question 32

Neural tube axis polarization: _______, where spinal neurons receive input from sensory neurons

Answer 32

dorsal

Question 33

Neural tube axis polarization: _______, where interneurons relay information between sensory neurons and motor neurons

Answer 33

middle

Question 34

Neural tube axis polarization: _______, where motor neurons predominate

Answer 34

ventral

Question 35

Homeobox genes _______ and _______ are in charge of dorsal domain

Answer 35

Pax3 Pax7 - these are TF's

Question 36

Homeobox genes _______ are in charge of middle domain

Answer 36

Pax6

Question 37

Homeobox genes _______ are in charge of ventral domain

Answer 37

Nkx6-1

Question 38

Morphogenic signals from its environment induce the D/V polarity of the neural tube. In the spinal region, **ventral** is imposed by the _______, and **dorsal** is imposed by the overlying _______

Answer 38

notochord epidermis

Question 39

Paracrine factors from the ectoderm and notochord induce secondary production centers in the Neural Tube itself: - Floor plate/Notochord produces: _______ - Roof plate/dorsal ectoderm produces: _______

Answer 39

SHH BMP4

Question 40

The ultimate identity of the gene expression pattern in each set of cells in the neural tube is dependent on: 1) its _______ from the morphogenic signaling center 2) the _______ of the received signal

Answer 40

distance duration