Development Of Multicellular Org II Flashcards Preview

Molecular Biology Exam 3 > Development Of Multicellular Org II > Flashcards

Flashcards in Development Of Multicellular Org II Deck (41):
1

Growth Cones travel towards target cells along what?

Predictable routes

2

Short term effects of NGF

- Effect on growth cone and Neurite extension

- Local, direct, and rapid

- INDEPENDENT of communication with the cell body

3

How many neurons in the brain?

10E11

4

Phase 2 of Neural Development

- Axons and Dendrites grow out along specific routes

- Setting up a Provisional but ORDERLY Network of connections b/w various parts of the system

5

Formation of the neural tube

- Starts w/ a Neural GROOVE on the Dorsal side of the Embryo

- Gradually deepens as Neural FOLDS become elevated

- Ultimately the folds meet and coalesce in the middle

- Closes to form a tube

6

Ex of Chemotactic Factors

1. Netrin (attractant)

2. Slit (repellent)

3. Semaphorin (repellent pushing Neuron to Brain)

7

Neural crest generate what cell types?

1. Neurons and Glial cells of the PNS

2. Epinephrine producing cells of adrenal gland

3. Many Skeletal and CT of the HEAD

8

T/F: Axons and Dendrites are NOT distinguishable at first?

True

9

Characteristics of Chemotactic Factors

- Secreted by cells

- Acts as guidance factors at strategic points along path

- May be Attractive or Repulsive

10

Neurulation

Closure of the Neural Tube

11

Roof Plate of the Neural Tube secretes what?

BMP and Wnt

12

What does Signal proteins secreted fro the Ventral and Dorsal side of the Neural Tube do?

- Act as opposing Morphogens

- Causing neurons at diff D/V positions to express Different Regulatory proteins

13

PNS origin

Derived from the Neural CREST

- Nerves, sensory neurons

14

What triggers the lasting change in synaptic strength?

Entry of Ca2+ through the Glutamate receptor

15

What regulates which growth cones synapse and where?

Signal from target tissue

16

The center of the Neural Tube is called what?

Neural CANAL

17

Typical axon length range

Less than 1mm

To

More than 1m

18

What Matrix molec favors growth? Which one inhibits it?

1. Laminin



2. Chondroitin Sulfate PTG

19

What forms a axon in Neuronal migration?

When a growth CONE starts migrating Fast

- Develops Axon-Specific Proteins

20

How many connections does one Neuron make?

About 1000

21

Neural crest Migration

Migrate extensively during or shortly after neurulation

22

The Fate of the Neural Crest cells depend on what?

Where the MIGRATE to

23

What rules are Synaptic Remodeling dependent on?

1. Axons from cells in DIFFERENT regions of Retina COMPETE for tectal neurons


2. Axons from NEIGHBORING sites which are excited at SAME time to strengthen synapses

24

Role of the Tectum

Responsible for Visual and Auditory Reflexes

25

Floor Plate of the Neural Tube secretes what?

SHH

26

Where do Neural Crest cells originate?

From the DORSAL End of the Neural Tube

27

Long term effects of NGF

- Effect on cell Survival

- Mediated by its receptor

- Uptake into cells via Endocytosis and stimulation do downstream signaling pathways

28

CNS origin

Derived from the Neural TUBE

- Brain, SC, Retina

29

Activity Dependent synaptic remodeling is dependent on what?

ELECTRICAL activity


And


Synaptic signaling

30

Why do 50% of Neurons die after they reach target cell?

- Made in excess

- Target cell produces limited amount of specific Neurotropic factors needed for survival

- Those that do not get enough die by PCD

31

Phase 1 of Neural Development

- Diff cell types (Neurons, glia) develop INDEPENDENTLY

- At widely separate locations in embryo according to local program

- UNCONNECTED

32

Neurons are produced in association with what?

Glial Cells

33

In the Neural Tube, what controls Lateral Inhibition and Positive Feedback?

Delta Notch

34

EMC mediated by what?

Homophilic Cell adhesion molecules

1. IG Superfamily
2. Cadherin Family

35

Growth cone behavior

- Dictated by its cytoskeletal Machinery

- Throw out Filopodia and Lamelopodia

36

What controls the movement of Growth Cones?

- Monomeric GTPases Rho and Rac

- They control the assembly/disassembly of ACTIN Filaments

37

Characteristics of Nerve Growth Factor.

- Belongs to fam of Neurotrophins

- NGF receptor is Tyrosine Kinase A

- Promotes the SURVIVAL of specific sensory neurons and sympathetic neurons

38

The two ways that Growth Cones find their way around.

1. ECM Environment
- Sensed by RECEPTORS present on membrane

2. Chemotactic Factors
- Released by Neighboring cells
- Attractive or repulsive

39

Growth Cone

- Spiky enlargement on the tip of the Axon/Dendrite

- Crawls through surrounding tissue

40

Phase 3 of Neural Development

- Continues in ADULT life

- Connections are adjusted and refined through interactions

- Distant regions are connected via electric signal

41

Contact Guidance

Growth cones follow a path taken by other cells