chapter 5 part 1 - growth and health nerovus system

child development

the neuron

nerve cells that handle information processing at the cellular level in the brain

dendrites

branches that recieve signals from other neurons

axon

long segment of a neuron which sends info to the other neurons

myelin

fatty sheath on some axons that insulates and speeds up neural transmission

terminal buttons

at the end of the axon are small knobs that release neurotransmitter

neurotransmitter (NT)

chemicals released across the synapse (carry info between neurons)

synapse

gap between neurons

the brain

divided into left and right hemispheres and linked by the corpus callosum

cerebral cortex

wrinkled surface of the brain; regulates many higher brain functions

brain development before birth

central nervous system originates in the prenatal neural plate

• developed 3 weeks after conception

• at 3-4 weeks it fold over to form a tube that becomes the brain and spinal chord

• 10 weeks in utero: nuerons start developing

• rapid development of nerve cells

• migrate to different areas of brain

• in the 4th mo axons start to acquire myelin (myelination)

• by 28 weeks the developing brain has about all the neurons it ever will

how many neurons are there at birth?

100 billion neurons

first couple of years

• number of dendrites and synapses increase

• networks of neurons become more complex

synaptic pruning

the brain will start weeding out unnecessary connections between neurons

myelination brain development

continues into adolescence

• improved reaction time, coordination, info processing

cerebral hemispheres

right and left halves of cortex specialize early

left hemisphere

typically specialized for language as a newborn

• more electrical activity here than right in response to speech for newborns

right hemisphere

typically specialized for use of metaphores and humor

• corpus callosum connects the two hemispheres

• complex thinking is the outcome between both hemispheres

specialization of brain systems

brain regions that are more active during processsing become more focused with development

specilization at different rates

brain regions that involve basic sensory and perceptual processes mature before those responsible for higher-order processes

during adolescence brain regions are what?

very responsive to rewards (especially from peers) while those areas responsible for self control specialize later in adulthood

prefrontal cortex during adolescence

may not be developed enough to curb strong emotions/motivation

• amygdala matures earlier

brain development occurs because?

of genetic programming and environmental influences

• deprivation of normal experience has a negative impact on the brain

hubel and weisel experiment

altered visual experiences of newborn kittens

• sutured one eye shut during a critical period in development

• resulted in permanent vision loss due to lack of normal connections

• critical periods are important

• importance of experience - expectant growth

plasticity

degree to which the developing brain is responsive to the individuals experiences

• the brain is relatively ___

romanian orphans

the longer the exposure to a neglect / deprived environment often meant more profound cognitive deficits

normal brain development can be thrown off course

• vulnerable to damage

• it may be able to recover from injury

• brain is felxible and has plasticity