Neurogenesis, Migration, and Post-natal Devel. Flashcards Preview

aNeuro Exam I- Lindsey's > Neurogenesis, Migration, and Post-natal Devel. > Flashcards

Flashcards in Neurogenesis, Migration, and Post-natal Devel. Deck (45):
1

Name some short-range (contact dependent) attractants for the growth cone.

  • cadherins
  • CAMs
  • collagen
  • laminin
  • fibronectin
  • proteoglycans

2

In the hindbrain (rhombencephalon), ____ plays a role in defining the identity of each segment.

cell death

3

What is multiple/polyneuronal innervation?

each muscle fiber is initially innervated by several motor neurons

4

When do the caudal portions of the corticospinal tract become myelinated?

after birth

5

Synapse formation involves _____ to a _____.

conversion of the growth cone to a presynaptic terminal

6

What physical changes are seen in apoptosis?

  • nuclear and cytoplasmic condensation
  • DNA fragmentation

7

Name 2 ways the growth cone is guided.

  1. long range chemotaxis
  2. local subtle cues (contact dependent)

8

What are semaphorins?

long range (diffusible) repulsive molecules

9

Normally, during the first postnatal year, the density of cortical dendritic spines ____ as dendritic spines ____.

increases; thicken

10

What is the difference btw an axon and a dendrite?

  • axons= long, send signals to target neurons
  • dendrites = shorter, stubbier, receive signals from input neurons

11

At birth, the density of neural connections is ____.

low

12

_____ serve as important regulators of neuronal survival, development, and function.

Neurotrophins

13

How does microcephaly occur?

not enough neurogenesis --> small brain

14

What are netrins?

long range (diffusible) attractant OR repulsive molecules

15

Growth cone guidance cues over long distances are _____.

diffusable

16

What can disruption of axon outgrowth in development lead to?

mental retardation

17

What is selective synapse elimination?

reducing the excess of contacted cells from multiple motor neurons innervating one muscle fiber to a 1:1 relationship

18

The neural crest dorsal stream gives rise to the _____.

pigment cells

19

____ and _____ are components of the ECM that are involved in neural crest cell migration.

Laminin and fibronectin

20

What induces differentiation and formation of processes?

neurotrophins

21

What do cadherins, CAMs, collagin, laminin, fibronectin, and proteoglycans all have in common?

they are short-range (contact dependent) attractants for the growth cone

22

In MS, there is ______ of the CNS axons.

demyelination

23

Neutrophins interact with membrane receptors that are members of the tropomyosin-related kinase (Trk) family, including ____, ____, and _____.

TrkA, TrkB, and TrkC

24

Name some short-range (contact dependent) repellants for the growth cone.

  • semaphoris
  • ephrins
  • tenascin

25

Name 7 neurotrophic factors.

  1. NGF
  2. BDNF
  3. NT-3
  4. NT--4/5
  5. CNTF
  6. LIF
  7. cardiotropin

26

How are GABA receptors different en utero?

  • receptors have many different subuints and isoforms
  • eq potential for Cl- is lower
  • Cl- levels are higher
  • activation of GABA receptors is excitatory

27

What do neurotrophic factors do?

promote cell survival

28

What is the neurotrophic hypothesis?

there is a limited amount of nutrients and trophic factors provided by the synapse targets to establish proper neuronal connections

29

What do semaphoris, ephrins, and tenascin all have in common?

they are short-range (contact dependent) repellants for the growth cone

30

CNS neurons appear to need _____ for survival.

multiple neurotrophic factors

31

Even if axons can be induced to grow across a lesion, what will probably go wrong?

it's unlikely that they will make the same connections as before the injury

32

What is the growing tip of the axon called?

the growth cone

33

The neural crest ventral stream gives rise to the _____.

sensory, autonomic, and enteric ganglia

34

Synapse elimination is due to _____.

competition for the target (NOT death)

35

_____ are involved in outgrowth, adhesion, and fasciculation.

CAMs

36

When does myelination begin?

during embryonic development in the periphery

37

These are long range (diffusible) attractant molecules.

netrins

38

Local growth cone guidance cues are ______ and require _____.

bound to cell membranes or ECM and require direct cell contact

39

______ are examples of short-range contact dependent signals.

CAMs

40

_____ abnormalities are associated with Down's Syndrome.

Dendritic

41

Where is the first CNS location that is myelinated? When?

the spinal cord @ the end of the 1st trimester

42

____ is associated with abnormal social/emotional behaviors.

ASD

43

During the first prenatal year, the brains of ASD show ______, especially in white matter areas, and _____.

abnormally high increases in size; neuronal cell bodies are smaller and dendrites branch less

44

_____ inhibit apoptotic cell death programs.

Neurotrophic factors

45

These are long range (diffusible) repulsive molecules.

semaphorins, netrins