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Flashcards in Axonal Growth Lec03 Deck (79)
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1

____ changes shape at decision points

growth cone

2

how do neurons start (before polarization)?

round, with no obvious processes

3

___ defines the polarity of the neuron

the axon

4

where are growth cones located?

the tip of the axon

5

what are lamellapodium? 

what do they contain? 

fan shaped sheet at the tip of the axon

contain actin filaments and microtubles

6

what are filopodia? what do they contain?

fine processes extending out from lamellapodium

have actin filaments

7

___ growth cone form and disappear rapidly

filopodia

8

___ dictates direction of growth - in lamellipodia / filopodia

Filamentous actin (F-actin) 

9

____ gets incorporated into F-actin at leading edge

 Gobular actin (G-actin)

10

F-actin Binding Proteins cause ___ and ___

retrograde flow & growth cone turning (by causing depolymerixation)

11

 attractive cue increases ___ and decreases ___ 

↑ polymerization/assembly, ↓ retrograde flow (goes toward the attractive cue)

12

functional difference ebtween MT and F-actin 

MT are responsible mostly for axon elongation

f-actin dictates direction

13

 ___ make the cytoskeleton core

Microtubules (they are strong and stable)

14

Acetylated microtubles only in ____

axons

15

 Tyrosinated microtubules ↑ in ____

lamellipodia

16

where is f actin found?

in lamellipodium and filpodia

17

Contact repellants include

Semaphorins and Ephrins

18

Contact attractants include

1. peipheral ECM

2. CAM

3. Cadherins

19

___ are attractants inthe periphery, but are not well understood in the CNS?

what are examples of each?

ECM molecules

attractants - laminins, collagens, fibronectin

not well understood? repellants? -- proteolgycens, glycoproteins, hyaloruonan

20

homolphilic binding of Cam 

triggers cytoplasmic kinases of growth cone

21

what is Ca independent signaling? dependent

indepdent - CAM

 

Depdendent - caDherins

22

homophilic binding of cadherins triggers

intracellular signals --> actin binding &
organization

23

axon guidance signsla re either ___ or ___

1. nondiffusable and short range

2. or diffusable and long range

24

the contact attraction and repulsion signals are ___

nondiffusable and short range

25

the chemoattractants and chemorepulsive signals are 

diffusable and long range

26

what does the binding of axon guidanc emolecules to receptors on growth cones activate?

signaling cascades that result in the reognization of growth cone cytoskeletons --> controlling the  direction and rate at which the growth cone moves

27

attractive interactions (contact attractants and chemoattractants) promote ____

actin polymerization

28

repellant interactions promote ____

actin depolymerization and growth cone collapse

29

lamins, collagens, and fibronectins bind to ___

integrin receptors

30

___ has been associated with bundling (fasiculation) of groups of axons as they grow

L1 CAM