Infancy - physical development Flashcards
Body growth
Babies grow at a faster rate in the first year: weight doubles at 5 months and triples at the end of 1st year to 22 lbs.
Babies get fat in early months to maintain body temp: 1 year olds lose “baby fat” and lowers fat: body ratio until puberty
Cephalocaudal principle
Growth is from head to tail
Proximodistal principle
growth goes from middle of the body out: “near to far”
hierarchical integration
simple skills are integrated into more complex movement (ex: raisin in a cup given to child, they start off by reaching, then grasping, then pinching and releasing)
independence of systems
different body systems grow at different rates
Early Fine Motor Skills
eye-hand coordination (reaching):
- pre-reaching (0-3 months): swiping at object
- visually directed reaching (3-5 months): more looking and intentional movements toward object
-object manipulation (grasping):
- grasp reflex → ulnar grasp: focus of the middle to pinky fingers of grasping object → neat pincer grasp: using pointer finger and thumb to pinch specifically at object
4 months: Ulnar palmar grasp
hold an object you give her in her palm while gently wrapping one or two of her fingers, excluding the thumb, around it. She won’t have a strong grip on the object at this point, so it may roll away from her hand.
Brain growth
Neurons start producing by week 7 of prenatal dev and most of the billions of neurons is produced by the middle of prenatal dev.
Neonate’s brain = 25% adult brain
Age 2 = 70%
Synapses
Brain growth in 1st year = peak for connections among neurons. Tiny gaps where communication takes place
Neurotransmitters
release/reception of chemicals that help neurons communicate across synapses
Axon
Long connecting fibers that release neurotransmitters
Dendrites
Short branch-like fibers that receive neurotransmitters
Synaptic exuberance/overproduction
spurt in new connections between dendrites and axons
Myelination
In fetal period (~14th week): axons are wrapped in myelin sheath = white fatty substance, to increase communication speed; fast in the 1st year and slower rate after 40
Synaptic pruning
“use it or lose it”: unused synaptic connections wither while used ones become stronger
Brain specialization
neurons in diff parts of brain have specialized functions. Brain = 3 main regions - hindbrain, midbrain, forebrain
hindbrain + mindbrain
mature earliest + perform basic biological functions (breathing, heart beating, balanced body movements).
forebrain
2 main parts: limbic system + cerebral cortex
limbic system
includes hypothalamus, thalamus, hippocampus
hypothalamus
small, size of peanut and plays a role in monitoring and regulating basic animal functions, hunger, thirst, body temp, sexual desire, hormones
Thalamus
receiving and transfering sensory info from body to the brain
Hippocampus
responsible for your memory and learning
hippocampus
cruical in memory, transferring from short-term to long-term memory
cerebral cortex
85% of brain’s weight; basis of human abilities: speaking, understanding language, solving problems, thinking concepts, ideas, symbols
lateralization
specialization of the two hemispheres:
left = language + processing info sequentially step by step
right = spatial reasoning + processing info holistic integrative way
Four lobes of each hemisphere
temporal, parietal, frontal, prefrontal
occipital lobe
rear of each hemisphere - process visual info
temporal lobe
lower side of each hemisphere - process auditory info
parietal lobe
Above temporal lobe process info from body senesations
frontal lobe
behind the forehead = at the center of advanced human brain processes, producing language and making decisions
preforntal cortex
foremost part of frontal lobe - most recently evolved, specialized abilities for planning/organizing info to direct behavior
Plasticity
Highly responsive to environmental circumstances. High in plasticity because infant brain is not as specialized
common cultural theme of infant’s social life
- infants are with their months constantly within all cultures
- about 6 months, most daily infant care is done by older girls rather than the mother
- infants are around many other people in the course of a day
- infants are held or carried almost constantly
- fathers are usually remote/absent during 1st year
two most influential theories of infant’s social development
Erik Erikson and John Bowlby
Erikson’s 8 stage theory applying to infancy
developmental crisis for each stage
For infancy: trust vs mistrust: infants are dependent on others for survival, require others to provide for their needs and have someone who can trusted to care for them and be a reliable source of nourishment, love and protection. If love and care are lacking, infants may mistrust caregivers and others, shrinking from a seemingly harsh and unfriendly world. Builds on previous stages as foundation for future social dev
Bowlby’s Attachment theory
importance of infant’s relationship with primary caregiver. Bowlby believed that this relationship influenced emotional/social development not only in infancy but other stages as well.
Caregiver being sensitive and responsive = help infant learn to trust others in social relationships
