development Flashcards
What is a zygote undifferentiated_
a bunch of cells that don’t have specific function
What is a zygote made of?
Egg & Sperm
What does a zygote produce?
it produces all the cells in the body
What is a blastula?
it is a ball of cells that are still unspecified
What is the ectoderm?
the outer layer of the blastula
How many tissues does the ectoderm develop to? What kind of tissues?
- develops into 2 tissues
- skin cells
- brain cells
What is the Neural tube?
-it contains cells that divide & turns into the Central Nervous System
- it also becomes the back
Where is the neural crest located?
Peripheral Nervous system
Where is the Neural tube located?
Central Nervous System
Where does our “gut” feelings reside?
- the Neural Crest
- brain controls these cells, but they have a mind of their own
What is the 1st stage of neural development?
Proliferation
- cell division occurs
What is the 2nd stage of neural development?
Migration
- results in neuroblasts
What are neuroblasts?
- Cells that are done dividing
- Their fate is to become neurons
What occurs in migration?
- When each cell is done dividing, they move out
- they keep moving until signals make it stop
What is the 3rd stage of neural development?
Differentiation
- goes on for a long time
- cell bodies create its extensions
- when neuroblasts become a neuron
How do target cells work?
- they release neurotrophic factors
- they are sent back to the body to notify brain about synapse
What kind of factors exist in target cells?
- NGF (nerve growth factor)
- BONF (brain derived neurotropic factor)
What is the 4th stage of neural development?
Pruning & Cell Death
What is pruning?
Pruning is when cells withdraw axons if no synapse
What is apoptosis?
Genetic program for cell death too little neurotrophic factor
- clean cell death
What is the 5th stage?
Myelination
- occurs when things are stabilized
What are 2 kinds of glias?
- Oligodendroglia
- only for CNS - Schwann Cell
- PNS
What makes toxins different than toxicants?
- toxins are from nature
- toxicants are human made
What can substances do to the brain?
- it can have permanent effects on it
- effects are greater during early development
- all stages of development are vulnerable
What are the different windows for different development sections?
- Sensory function happens first
- motor/language happens next
- finally, higher cognition occurs
Where are the cell bodies located in?
Gray matter
What part of a cell is in the white matter?
the axons
what kind of matter is in the corpus callosum?
White matter
What is the corpus callosum?
- it is a huge tract
- can be seen using transmission electron micrograph
What is Amblyopia?
- eyes out of alignment
- dominant eye takes over
- common in babies
- usually wears off
What occurs in normal eyes when axons are competing for space?
- pruning occurs
- allows each dendrite to sit in its own column
What occurs in abnormal eyes when axons are competing for space?
- opened eye takes over the closed eyes space
- doesn’t allow dendrites to grow in closed eye
- creates lazy eye
What is the most common transmitter in the CNS?
Glutamate
What is the AMPA receptor?
- it is an ionotropic receptor
- when it is open, it allows ions to go through
What do you need for a strong synapse?
- you need a lot of action potentials and NA+
- you need both axon terminals/ receptors
How can NMDA be open?
- can only be opened if enough excitation from AMPA
- also opens calcium
- more ampa is released
- stronger synapse
What are the steps in NMDA coincidence detection?
- several AMPA receptors in close proximity used simultaneously results in increased depolarization
- NMDA opens & lens CA into the dendrite
- CA starts a chemical cascade that results in more AMPA receptors being put into the membrane
results in a STRONGER synapse
How do dendrites respond to enriched environment?
- create more dendrites
- result in better performances
What happens to rats when going from adolescence to adulthood?
- loss of neurons between puberty & adulthood in medial prefrontal cortex & in amygdala
What happens to rats and humans when going from adolescence to adulthood?
- synapses are lost in prefrontal cortex
- myelination increases
How does the adult brain change?
- proliferation in 2 brain areas only
- increase in glias
- no long axon growth
- grow and prune dendrites
- add and subtract synapses
