CHAPTER 10

Question 1

Neural crest cells are derived from the ectoderm, it
is important that it has been called the “____________”.

Answer 1

fourth germ
layer

Question 2

• a population of multipotent progenitor cells
  that can produce tissues that emerges from
  the dorsal neural tube during early
  development.
• has the capacity to differentiate into
  particular cell types associated with multiple
  cell lineages

Answer 2

Neural crest

Question 3

_________ is the process by which
neural crest cells are specified from the
neuroectoderm

Answer 3

Neural crest induction

Question 4

Stages in the Specification of Neural Crest Cells

Answer 4

• NEURAL PLATE INDUCTIVE SIGNALS: BMPs,
Wnts, FGFs, Notch&raquo_space;
• NEURAL PLATE BORDER
SPECIFIERS: D115, Pax3/7&raquo_space;
• NEURAL CREST
SPECIFIERS: Fox D3, Twist, Snail&raquo_space;
• NEURAL
CREST EFFECTORS: MITF, Rho GTPases, Kit, Ret

Question 5

● _____________
(early-migrating NCC) - come around the
neural tube and start coming downward
THROUGH the somite.
● __________
(late-migrating NCC) - around the somite
on the outer rim.

Answer 5

VENTRAL-LATERAL MIGRATION
DORSAL-LATERAL MIGRATION

Question 6

The ______ is largely the product, and the
evolution of jaws, teeth, and facial cartilage
occurs through changes in the placement of
these cells

Answer 6

head

Question 7

Neural crest cells from the vagal and sacral
regions form the _______ of the gut
tube and control ________

Answer 7

enteric ganglia
intestinal peristalsis

Question 8

Only these particular neural crest cells
generate the endothelium of the aortic arch
arteries and the septum between the aorta
and the pulmonary artery

Answer 8

Cardiac neural crest cell

Question 9

The ___________ perform one
of the longest migration because they are
chasing a moving target—the caudal most,
or distal extent of the growing gut.

Answer 9

enteric neural crest cells

Question 10

________, whose axons travel from
the spinal cord to a specific muscle.

Answer 10

Motor neurons

Question 11

Two main migratory paths of trunk neural crest cells

Answer 11

Ventral lateral migration
Dorsal lateral migration

Question 12

______ whose axons must cross the midline plane of the embryo to innervate targets on the opposite side of the central nervous system

Answer 12

Commissural neurons

Question 13

The ____, where axons originating in the retina must find their way back into the brain

Answer 13

Optic system

Question 14

Three steps of axonal specificity

Answer 14

Pathway selection
Target selection
Address selection

Question 15

The axons travel along a route that leads to a particular region of the embryo.

Answer 15

Pathway selection

Question 16

The axons, once they reach the correct area, recognize and bind to a set of cells with which they may form stable connections.

Answer 16

Target selection

Question 17

The initial patterns are refined such that each asxom binds to a small subset of its possible targets.

Answer 17

Address selection

Question 18

Neurons at the ventrolateral margin of the vertebrate neural tube become ________, and one of their first steps toward maturation involves target specificity.

Answer 18

motor neurons

Question 19

The axonal growth toward the dorsal muscle is because Lim1 induces the expression of _____, which is the receptor for the chemorepellent protein ephrin A5 that is made in the ventral part of the limb bud.

Answer 19

EphA4

Question 20

Motor neurons seek their targets through _____ “______”

Answer 20

intrinsic programs

Question 21

The ephrins and the semaphorins, are most well-known membrane proteins (but not exclusively) for their role as ________ during the patterning of axonal anatomy.

Answer 21

repellent guidance cues

Question 22

The proteins of the semaphorin-3 family, also known as _______, are secreted proteins and collapse the growth cones of axons originating in the dorsal root ganglia.

Answer 22

collapsins

Question 23

Types of commissural neurons

Answer 23

Shh
Netrin
Slit and Robo

Question 24

______ is made in and secreted from the floor plate and is distributed in a concentration gradient that is high ventrally and low dorsally

Answer 24

Shh

Question 25

That other factor is ______, which is identified by an assay developed to screen for diffusible molecules that might guide the axons of commissural neurons.

Answer 25

Netrin

Question 26

_______ are needed as a driving force for a commissural axon to cross the midline and grow way from it.

Answer 26

Repulsive cues

Question 27

In Drosophila, ____ is secreted by the glial cells at the midline of the nerve cord, and it acts to prevent most axons from crossing the midline from either side.

Answer 27

Slit

Question 28

The trigeminal ganglion has three main divisions.

Answer 28

Opthalmic nerve
Maxillary nerve
Mandibular nerve

Question 29

It is a protein involved in the development and growth of tissues throughout the body

Answer 29

BMP4

Question 30

_____ is a protein on the surface of nerve cells that can bind to BMP4

Answer 30

BMP

Question 31

The activity of the synapse releases _______ from storage vesicles in the growthcone.

Answer 31

N-cadherin

Question 32

During mammalian development, all muscle cells that have been studied are innervated by at least _____ axons.

Answer 32

two

Question 33

When one of the motor neurons is active, it suppresses the synapses of other neurons, possibly through a ________ mechanism.

Answer 33

nitric oxide-dependent

Question 34

_________ is a technique used by researchers to visualize and trace the connections of neurons in an organism.

Answer 34

Brainbow

Question 35

As the RGCs differentiate, their position in the inner margin of the retina is determined by ______ (N-cadherin and retina-specific R- cadherin) in their cell membranes.

Answer 35

cadherin molecules

Question 36

In non-mammalian vertebrates, the final destination for RGC axons is a portion of the brain called the _______, while mammalian RGC axons also go to the lateral geniculate nuclei. At many points, the journey of RGC axons within the brain occurs on an astroglial substrate.

Answer 36

optic tectum

Question 37

Both across the midline (optic chiasm) and on the “optic tract” to the optic tectum, RGC axons of non-mammalian vertebrates travel over glial cells whose surfaces are coated with _______.

Answer 37

laminin

Question 38

As in the retina, _____ (a receptor of Slit) appears to be the major mediator of RGC guidance at the chiasm.

Answer 38

Robo2

Question 39

_________ investigates how the nervous system forms and evolves from embryonic stages through adulthood.

Answer 39

Developmental neurobiology