Module 4 Physical Development PDF

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Module 4: Physical Development 1. Describe the states and organized behaviours of newborns -

Table on page 139 Reflex: an involuntary and automatic response to a stimulus Survival reflexes: inborn responses such as breathing, sucking and swallowing that enable the newborn to adapt to the environment Primitive reflexes: reflexes controlled by the subcortical areas of the brian that gradually disappear over the first months of life - Important diagnostic indicators to developmentalists - Remnants of out evolutionary history that have outlived their original purpose - Ex. Babinski reflex

1.1. Describe developmental changes in infant states -

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Levels of sleep and wakefulness that young infants display Neonates spend 70% of 16 to 18 hours sleeping a day 2 to 6 weeks babies sleeping 14 to 16 hours 3 to 7 months begin to sleep through the night between 9.7 to 15.9 hours REM sleep accounts for half of babies sleep from two weeks before born to 2 months after birth - Steadily declines after birth - Allows the nervous system to develop Autostimulation theory: REM sleep in infancy is a form of self-stimulation that helps the central nervous system develop

1.2. Describe Sudden Infant Death Syndrome and ways to reduce its incidence -

Unexplained death (crib death) of a sleeping infant who suddenly stops breathing Leading cause of post-neonatal death Most likely 2 to 4 months old and have a respiratory infection Sleeping on stomach in tight clothing Abnormalities in arcuate nucleus To reduce incidence of SIDS: sleep on stomach, sleeping on hard surfaces, no unnecessary objects, lightlty clothed, smoke free zone, breastfeed

1.3. Describe newborn reflexes, their development and significance -

Crying declines after 3 months, linked to maturation of the CNS Shrill non rhythmic cries are perceived as sickly

2. Describe patterns of growth and maturation and the factors that influence them 2.1. Describe patterns of growth and maturation -

Growth is very uneven in infancy A newborn's head is 70% of its eventual adult size Cephalocaudal development: sequence of physical maturation and growth that proceeds from the head (cephalic region) to the tail (caudal region) Trunk grow fastest in the first year Until adolescent growth the legs grow the fastest, during adolescence the trunk grows fastest Proximodistal: a sequence of physical maturation and growth that proceeds from the center of the body to the extremities

2.2. Describe the development of the skeleton -

During the prenatal period soft cartilage ossifies into bony material At birth the bones are a source of blood cells During postnatal development only specific bones are a source of blood cells Neonates skull is soft and easily compressed to allow passage through the birth canal Fontanelles (6) gradually filled in by age 2 with sutures that allow expansion as the brain grows Skeletal age: a measure of physical maturation based on the child skeletal development Neonates are born w/ all the muscle fibers they will ever have

2.3. Describe some of the factors that contribute to variability in growth and maturation -

People from asia, south america and africa are smaller than north americans, northern europeans and australians People from asia, south america and africa mature faster than europeans and americans Heredity and environmental factors accounts for these differences 3. Describe brain development during childhood and adolescence

3.1. Describe changes in brain growth -

Brain growth spurt: the period between the seventh prenatal month and 2 years of age when more than half of the children's eventual brian weight is added Glial cells account for the brain growth spurt At birth the most developed areas are the lower subcortical brain center

3.2. Describe changes in quantity of neurons

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Neurons: nerve cells that receive and transmit nerve impulses 100-200 billion nervous have already formed at the end of the second trimester of pregnancy Neuron are produced in specific areas of the brian such as the hippocampus Neurons have the potential to serve any neural function depending on where it is in the brain Half the neurons produced in early life also die in early life

3.3. Describe changes in quantity of synapses -

synapses : connective tissue juncture between one nerve cell and another Synaptogenesis: formation of synapses Avg. infant has more neurons and neural connections than adults do Synaptic pruning: synapses disappear if not stimulated - Starts near birth and completed near the end of sexual maturation

3.4. Describe changes in myelination -

Glia: nerve cells that serve supportive functions Oligodendrocytes produce myelin At birth sense organs and the brain are myelinated As neural pathway between the brain and skeletal muscles myelinate the child's motor skills increase Reticular formation and frontal lobe at allow concentration are not fully myelinated until puberty

3.5. Describe changes in plasticity -

Plasticity: capacity for change a developmental state that has the potential to be shaped by experience Austin Riesen: raised chimpanzees in the dark and realized retinal neurons were under developed

3.6. Describe changes in brain specialization -

Cerebral lateralization: the specialization of brain function in the right and left hemisphere Starts in the prenatal period 4. Describe the development of motor skills in infancy and childhood

4.1. Describe milestones of locomotor development

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Tells us little about the child's future developmental outcomes Table page 156

4.2. Describe the two basic trends in locomotor development -

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Motor development proceeds in a cephalocaudal direction and at the same time in a proximodistal way - Kicking movements are dismissed as unintentional movements Galloway contradicts the cephalocaudal rule - Infants alters leg movements when rewarded - Goot contact made with toy before hand contact

4.3. Describe the factors that contribute to variability in locomotor development 4.4.1. Describe individual differences in locomotor development using a concrete example 4.4.2. Describe the contribution of maturation -

Unfolding of genetically programmed sequence of events where muscles and nerves mature downwards and outwards Cross cultural research - infants around the world progress in similar steps Identical twins show experience has an effect

4.4.3. Describe the contribution of experience -

Maturation is necessary but not sufficient for development of motor skills Need to opportunity to practice skills Cross cultural research- enriching experiences accelerate the process Heavily influenced by parental practices Jamacican mothers promote early motor development by stretching limbs

4.4.4. Describe the contribution of motivation (aka the dynamic systems theory) -

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Do not view motor skills as genetically programmed View each new skill as a construction that merges as infants actively reorganize existing motor capabilities into new and more complex action systems Infants hope to acquire and perfect new motor skills that will help them to explore or accomplish goals

4.4.5. Describe how advances in motor skills influence the development of perceptual skills

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Voluntary reaching - Primitive thruts (prereaches): uncoordinated swipes at objects in the visual field - Proprioceptive information: sensory information from the muscles, tendons and joints that help one to locate the position of one's body - Reflexive palmar grasp Manipulatory skills - 4 to 5 months grasp thing with both hands - Fingering 4 to 6 months - Ulnar grasp: infant grasps objects by pressing the fingers against the palm - Pincer grasp: thumb is used in opposition to the fingers, enabling dexterity at lifting and fondling objects - End of first year - 16 months children can scribble Optical flow: the perceived movement of objects in the visual field

5. Describe the causes and correlates of physical development 5.1. Describe biological influences -

Physical and motor development is reasonably consistent from child to child Regular maturational sequences are shared among humans and are species specific attributes Female identical twins reach menarche w/in 2 to 3 months of each other compared to fraternal who are 10 to 12 months apart

5.2. Describe hormonal influences -

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Fourth prenatal month the thyroid is formed and produces thyroxine - Essential for normal growth of the brain and body pituitary gland “master gland” at the base of the brain and trigger the release of hormones from all endocrine glands - GH stimulates rapid growth and development of body cells - Small amounts of GH several times a day, 60 to 90 mins after children fall asleep Pituitary secretions stimulate estrogen production and testosterone

5.3. Describe environmental influences -

Nutrition, illness and the quality of care children receive Nutrition is the most potent environmental influence Undernutrition: if neither prolonged nor serve children will recover

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Catch up growth: short term growth deficits because of malnutrition grow rapidly to regain growth trajectory - Masamus: too little protein and calories - Very firal and wrinkled - Remain small in stature and imapired development - Kwashiorkor: extended stomach b/c of lack of protein - When weaned from breast milk - Vitamin and mineral deficiencies - Western world lower socioeconomic backgrounds - Iron deficiency anemia - Slows growth rates and associated w/ poor intellectual and motor skill development Overnutrition: - Obesity: 20% above ideal weight for their height, age and sex Illness - Is adequately nourished has little effect on physical growth Quality of care - Nonorganic failure to thrive: infant growth disorder caused by lack of attention that causes growth to slow dramatically or stop - Usually by 18 months of age - Caregivers are cold and aloof - Deprivation dwarfism: - 2 to 15 years of life - Small stature and dramatically reduced rates of growth, low GH - Lack positive involvement from others, namely primary caregivers - Individual or family therapy help or placing child w/ another family...