Neural Crest Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

What do neural crest cells become?

A

Peripheral nervous system, endocrine cells, pigment cells, facial cartilage and bones, connective tissues

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

When are the neural crest cells specified? Where do they come from?

A

Very early on in the ectoderm. They come from the edge between the neural tube and the epidermis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What happens to the neural crest cells as the neural tube forms?

A

They undergo an EMT, delaminate, and migrate to become various cell types

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What determines what cell type a neural crest cell will become?

A

Where it came from and which migration path it’s following

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the 4 types of neural crest cells?

A

Cranial, cardiac, trunk, vagal/sacral

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What types of cells do the cranial neural crest cells become?

A

Neurons, glia, melanocytes, facial cartilage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the two migratory pathways trunk neural crest cells can take?

A

Dorsal and ventral

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Which of the two migratory pathways is the default for the trunk neural crest cells?

A

Dorsal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What features arise from the trunk neural crest cells that went through the dorsal pathway?

A

Melanocytes - skin pigment cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What features arise from the trunk neural crest cells that went through the ventral pathway?

A

Sensory neurons in the dorsal root, sympathetic nervous system, adrenal medulla

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How are pigmentation patterns created?

A

Migration or death of melanoblasts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the 3 steps required for trunk neural crest cells to take the ventral pathway?

A
  1. Cells are blocked from taking the dorsal pathway
  2. First set of NCC migrate between the somites then are blocked
  3. Second set of NCC migrate through the anterior parts of the somites
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the sclerotome?

A

Anterior side of somites

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How do the somites keep the neural crest cells out of the posterior end of the somite?

A

They express ephrin and semaphorin-3F, which repulses the NCCs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Why do the neural crest cells need to migrate through the anterior end of the somite?

A

Keeps all the motor neuron axons in one place

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What part of the axon guides which direction it grows in?

A

The growth cone

17
Q

What is the axon growth cone?

A

Extension off the axon with lamellipodia and filipodia constantly probing to make the axon grow one way or the other

18
Q

Which protein complex in the axon growth cone controls directional growth?

A

CLASP/APC

19
Q

How does the CLASP/APC complex in axon growth cones control directional growth?

A

Causing more microtubule growth and lamellipodial extensions when it is phosphorylated

20
Q

What causes the CLASP/APC complex in the axon growth cones to become phosphorylated?

A

Attractive signals. Repulsive signals stop the phosphorylation from happening

21
Q

What are the 3 steps in axon targeting?

A

Pathway selection: follows a general route through the to a general body region
Target selection: recognizing and going towards target cells in that general body region
Address selection: recognizing and going towards a specific subset of cells

22
Q

What are the two signals that are guiding the growing axons to or away from limb buds?

A

Semaphorin and ephrin

23
Q

How are semaphorin and ephrin signals arranged in the limb bud? How do neurons respond?

A

Semaphorin is expressed in the dorsal side of the limb bud, and neurons that are receptive to semaphorin signalling will grow towards that signal and will stay away from the ephrin signal. Ephrin is on the ventral side and will attract some neurons and repel others. Neurons that are repelled by both don’t go to the limb bud

24
Q

What are the 3 subpopulations of sensory neurons? What order do they stop and what do they connect to?

A

Pain and temperature receptors: stop first in the dorsal part of the spinal cord and connect to interneurons
Mechanoreceptors: stop second in a slightly less dorsal part of the spinal cord and connect to interneurons
NT3 responsive neurons: stop last in the ventral part of the spinal cord and connect the motor neurons to form reflexes

25
Q

What are the 3 diffusible signals involved in pathway selection in axon growth?

A

netrins/DCC receptor, Unc-6, Slit/Robo receptor

26
Q

What is target selection?

A

A neuron will refine which signals it’s receptive to and will follow different signals than before. It will be simultaneously attracted by some signals and repelled by others

27
Q

What are the 4 signals involved in target selection?

A

Neurotrophins, nerve growth factor, brain derived neurotrophic factor, endocannabinoids

28
Q

Why are endocannabinoids important for neuron development?

A

Critical for finding their correct target and forming the correct connections

29
Q

What is address selection?

A

Forming a synapse and then reducing the number of axons around through competition

30
Q

How does address selection happen? What signals are involved?

A

The growing neurons detects beta2-laminin in the extracellular matrix and stops growing. The neuron produces agrin, which causes the muscle cell to cluster their neurotransmitter receptors. Then competition between axons will prune them so there’s not too many in one place

31
Q

How many neurons will connect to a muscle cell in vertebrates?

A

One