Development of Multicellular Organisms II Flashcards
Describe phase 1 of neural development
different cell types (neurons, glial cells) develop independently at widely separate locations in embryo according to local program and are unconnected
Describe phase 2 of neural development
Axons and dendrites grow out along specific routes setting up a provisional but orderly network of connections between various parts of the nervous system
Describe phase 3 of neural development
continues into adult life, connections are adjusted and refined through interactions with distant regions via electric signals
Neurons are produced in association with ____ cells
glial
Where do neurons and glial cells develop from?
ectoderm
Where is the CNS derived from? the PNS?
CNS: neural tube
PNS: neural crest
What controls differentiation into neurons (lateral inhibition and positive feedback)?
delta notch
The neural crest originate at the ______ end of the neural tube
dorsal
Fate of the neural crest cells depend on what?
where they migrate to and settle
What does a typical immature neuron have?
cell body, long axon, several short dendrites
Growth cone behavior is dictated by its ______ machinery
cytoskeleton
Growth cones grow out of ______ and _____
filopodia and lamelopodia
Monomeric GTPases Rho and Rac control the assembly/disassembly of _______ which control movement of growth cone
actin filaments
What are chemotactor factors released by?
neighboring cells
What are the two important classes of hemophiliac cell adhesion molecules?
immunoglobin superfamily
cadherin family
Ventral clusters of spinal cord neurons develop as ____ neurons send out long axons to connect with specific subset of muscles
motor
Intermediate location has ______ that connect specific set of nerve cells to each other
inter neurons
Describe chemotactic factors
secreted by cells, act as guidance factors at strategic points along path. May be attractive and repulsive
What does the first stage depend on?
nectarine secretion
Binding of netrin to its receptor causes opening of ______ channels
TRPC (transient receptor potential C)
What does Slit do?
repels growth cones and blocks entry to the midline
Target produces limited amount of specific _______ factors needed for survival
neurotrophic
What was the first prototypical neurotrophic factor?
nerve growth factor (NGF)
What family does NGF belong to? what is the receptor?
family: neurotrophins
receptor: tyrosine kinase (TrkA)
What does NGF do?
promotes survival of specific sensory neurons and sympathetic neurons
What is the short term effect of NGF?
effect on growth cone and neurite extension. Effect is local, direct, rapid and independent of communication with cell body
What is the long term effect of NGF?
effect on cell survival. Mediated by its receptor, uptake into cells via endocytosis and stimulation of downstream signaling pathways
What two rules are synaptic remodeling dependent on that rate spatial order?
- axons from cell in different regions of retina compete for tectal neurons
- axons from neighboring sites which are excited at same time cooperate/collaborate to retrain and strengthen synapses with tectal neuron
neurons that fire together _____ together
wire
entry of ____ through the glutamate receptor ( _____ receptor) triggers lasting change in synaptic strength
calcium, NMDA
