Neuronal Migration Synapse Formation and Survival Flashcards
How do we get from a tube to the highly developed nervous system
Neuronal migration and axon guidance
True or False:
Wiring up the brain is a simple process
False
True or False:
Distance is a contributing factor of difficulty in the developing nervous system
True
What is a receptive field
The area that a receptor is able to respond to a stimuli
What stretch as the nervous system expands
Pioneer axons
How do the axons know where to grow
They follow chemical cues
True or False:
Pioneer axons guide neighboring axons
True
How many neurons in a new born and an adult
New born 300 billion
Adult 80 billion
True or False:
Each neuron has a single phenotype and one or a few neurotransmitters
True
One neuron can have how many synapses
700-1500
What maintain contact with the inner and outer edges of the wall of the neural tube
Radial glial cells
Where do cells proliferate in
The ventricular zone
Where do cells migrate into
The mantle zone
What does the mantle zone form
Gray matter
What do neurons travel along to get to their end resting place
Radial glial cells
Where do axons go as they move out from the cells
The marginal zone
What does the marginal zone form
White matter
True or False:
The mantle zone becomes most of the brain and cord
True
What is the key element responsible for the growth of an axons and dendrites toward its target
The growth cone
What is actin that collects at the surface of the growth cone called
Filopodia
What do filopodia do
Creep forward and grab onto the surface pulling the growth cone with it
What are the 3 main domains of the growth cone
- Central core
- Lamellipodium
- Filopodium
True or False:
The growth cone contains sensory structures to guide it by chemical cues
True
What are the motile domains of the growth cone
- Filopodium
2. Lamellipodium
What is the gradient effect
Chemical cues change in concentration so the growth cone knows which direction to head.
In the spinal cord what are the only remnants of the ventricular zone
Ependymal cells
True or False:
Radial glia maintain connections to the very surface of the cerebral cortex for a long time
True
How do the cells migrate in the cerebral cortex
The new cell goes behind the last cell that was laid down
In the cerebral cortex where are the youngest and oldest cells located
Youngest are superficial
Oldest are deepest
How many waves of neuronal migration occur in the cerebral cortex
6
What is a very protracted developmental process that starts during early brain development and continues through life
Synaptogenesis
Why is synapse elimination important
Because there are many more synapses formed than will be present in the adult animal
What are the 2 types of projection errors in migration
- Axons may project to the correct target but they may spread out too far (lack of precision or overshooting)
- Postsynaptic neuron or target receives inputs from the wrong number of afferents
What does myelin allow for
A reduced need for more cells
What are the 3 cells of the synapse
- Motor neuron
- Myofiber
- Schwann cell
What are the 3 steps in the formation of a CNS synapse
- Dendritic filopodium contacts axon
- Synaptic vesicles and active zone proteins are recruited to presynaptic membrane
- Receptors accumulate on postsynaptic membrane
What helps the development of brain function
Balance between genesis and elimination of cells and synapses
What is apoptosis
Programmed cell death
What does apoptosis do
Rapidly removes cells
Is apoptosis an inflammatory process
No
Throughout development of the human nervous system how many neurons may die regionally
More than half
About how many of the neurons die off that were present at birth
2/3
True or False:
The amount of neuron death varies across species
True
True or False:
Some neurotrophic factors block default apoptosis
True
What are 2 examples of diseases involving neurotrophic factors
- Huntingtons chorea
2. Parkinsons
What is huntingtons chorea
Loss of huntington protein which upregulates BDNF and the survival of striatum neurons
What is parkinsons disease
Death of dopaminergic neurons which repsond to Glial dopamine neuronal factor (GDNF) and Cortical DNF (CDNF)
What controls movement in utero
Midbrain because it is not conscious
True or False:
Synaptic changes occur throughout life
True
What is synaptic plasticity dependent on (5)
- Learning
- Experiences
- Environment
- Lifestyle
- Health
True or False:
Once the brain is developed plasticity decreases with age
True
