Date post: | 02-Dec-2014 |
Category: |
Documents |
Upload: | professorjcc |
View: | 355 times |
Download: | 1 times |
Chapter 3 Physical Development
3.1
Patterns of Growth
Cephalocaudal
CapGrowth starts at the top & moves downward.
Cephalocaudal (ceph alo caudal)Sequence in which the earliest growth always occurs at the top.
Large proportion of total body Occupied by head
Prenatal developmentEarly infancy
Growth starts at head Physical growthDifferentiation of featuresShoulders, etc. downward
Patterns of Growth
Cephalocaudal cont.Sensory & motor development
See objects before control torsoUse hands before walk or crawl
Nevertheless, use feet to touch something (12 weeks) before hands (16 weeks)
Patterns of Growth
Proximodistal
PenisSorry, all I could think of.
ProximodistalGrowth starts at center & moves outward
Proximodistal (proxi mo distal)(Sensory & motor development)
Sequence in which growth starts at center of body & moves toward extremities
Sensory & motor development Control muscles of trunk & arms
before hands
Patterns of Growth
Independence of Systems
Body systems grow & mature independentlyNervous system matures rapidlyBody size slower
Rapid Growth Slow Growth
Brain Development
Cephalocaudal principle indicatesBrain closer to adult size than any other physical structure
Brain Development
The Brain
At Birth 100 billion neurons Areas of brain do not mature uniformly.
Prefrontal cortex finished developing when?
NeuronsAxon Dendrites Myelin sheathTerminal buttonsSynapses
Brain Development
Axon
Carries signals away from cell body
Dendrites Carry signals toward cell body
Brain Development
Brain Development
NeuronInfo processing nerve cellAxons & dendrites
Myelin sheathLayer of fat cellsEncases & insulates most axonsMyelination continues into adolescenceHelps electrical signals travel faster down axon
How Do Infants Grow and Develop Physically?
Neurons
Terminal buttonsRelease neurotransmitters into synapses
SynapsesTiny gaps between neurons' fibers
Synapse
Changes in Brain Regions
1st yr’s of lifeNeurons change in 2 significant ways
1. Myelination2. Increase in neural pathways
How Do Infants Grow and Develop Physically?
24 monthsAt birth 1 month 3 months 15 months
The Development of Dendrite Spreading
Brain Development
Synapses: Tiny gaps between neurons' fibersNeurotransmitters
“Blooming” & “pruning”
How Do Infants Grow and Develop Physically?
Changes in Brain Regions
Blooming (development or increase) in synaptic overproduction
Vary considerably by brain region
Example of blooming in a region:Visual cortex
Blooming peaks @ 4 mo.'s
Changes in Brain Regions
Prefrontal cortex Higher-level thinkingSelf-regulationNot fully developed until @ 23 yrs.
Most prolonged development of any brain region
Peak of synaptic overproduction @ 3 yr ageAdult density achieved in adolescenceHeredity & environment affect timing
Changes in Brain Regions
Changes in Brain Regions
Pruning (decrease) in neurons
Unused connections replaced by other pathways or disappearVary considerably by brain regionBegins @ early adolescence & ends @ age 16.
How Do Infants Grow and Develop Physically?
40
70
60
0
50
30
20
10
Syn
aptic
den
sity
10,000100 200 300 400 500 600 1000 1500 2000 3000 4000 6000 8000800
Age in days (from conception)
Synaptic Density in Human Brain from Infancy to Adulthood
Adolescent Brain
http://dsc.discovery.com/tv-shows/discovery-presents/videos/understanding-the-brain-teenagers.htm
Increased Sophistication
Adolescence2nd wave of:
Overproduction of synapsesPruning
Prefrontal cortex changes rapidlyImproved control over:
PlanningAttentionGoal directed activity
Poor risk assessment
Increased Sophistication
AdolescencePreform poorly on tests of emotions
Late adolescence emotional processing moves to frontal lobe
Improvement in risk assessment
The BrainCerebral cortex
Covers forebrain like a wrinkled cap2 hemispheres (halves)Lateralization
Specialization of function in one hemisphere or other
Ex: Language, left hemisphere
Lateralization
Brain organized contralateral (other side)Information for right side transmitted to leftEach hemisphere has specific brain functions
http://www.youtube.com/watch?v=XxSmOOaXrHk
LateralizationHandedness:
Most right handFootedness:
Most right footOcular Dominance:
Right 2/3Left 2/3
Some neither Not related to hand dominance
Facial Asymmetry: Left side of the face is more expressive of emotionRight displays verbal information
Sex & Gender Differences in Brain Development
Girls better at left-brain dominated Language Better at understanding nonverbal cues
Jack did not notice Dr. mad
Boys better at right-brain dominated
Mathematical reasoning
Sex & Gender Differences in Brain Development
Equal, F&MAchievement motivationVisual or auditory learningAnalytic ability
Sex & Gender Differences in Brain Development (Females)
Corpus callosum Connects hemispheresThicker in females
Limbic systemsLarger
Frontal CortexDecision makingDenser
Sex & Gender Differences in Brain Development (Males)
AmygdalaFight or FlightLarger in males
More developed spatial skills
Sex & Gender Differences in Brain Development
Social rolesDependent upon cultureU.S. social bias
Girls expected to be nurturing & empathic Boys?
Sex & Gender Differences in Brain Development Males
More variation in personalityMore variation between males
In skills