CHD2220 Test Two Study Guide Chapter 5: Perceptual, Physical and MotorDevelopment in Infancy Infants gradually come to know people by mutual touch, speech, and glances. Gradually learn to fixate and track objects in space and control movements toaccess objectsPhysical Growth- First two years Changes in Height and Weight- Average newborn weighs 7 ½ lbs. - Average measurements are 20 inches from head to tow- Birth weight doubles by five months - Triples by first birthday- Gains 5-6 lbs. in 2nd year - 4-5 lbs. in third year- Height increases by half in 1st year- Additional 5-6 inches in 2nd year Changes in Body Proportions - Changes progress in two fundamental principles of physical growth: Cephalocaudal (Head-to-Tail) Principle: growth of the head and upper body precede growth in lower body.o 8 weeks after conception head in half fetus length. 25 % of length at birth, and 12% in adulthood Proximodistal (Near-to-Far) Principle: body grows from the center outward. o Torso develops prior to arms and legs, arms and legs prior to hands and fingers Childproofing the Environment- Light sockets, stairs, drop-offs, security gates, dangerous objects, and substances. Nutrition in Infancy- Breast milk of a mother contains nutrients in perfect proportion to the infant’s needs during the first 3-4 months of life. - Formulas made from cow’s milk are nutritionally acceptable for babies of mothers who cannot or choose not to breast-feed. - Infants need fats, proteins, carbohydrates, minerals and vitamins met adequately by both human milk and formula- Breast-feeding promotes early development of infant brain andpositive effects on long-term cognitive intellectual development, as well as immunological benefits- Infant’s immune system does not become effective until middleof first year. Vulnerable to infection Colostrum: a thin, yellowish fluid secreted by the breast for several days before milk is produced. Contain antibodies that cannot be duplicated in formula. - Babies that were breast-fed were not hospitalized as much as formula fed babies. Decrease in SIDS, diabetes, lower rates of obesity, less likely to develop ADHD- Mothers who breastfeed more quickly lose their pregnancy weight- American Academy of Pediatrics recommends mothers breastfeed infants for 6 months and continue 6 moths longer after solid food is introduced- % of women who make an attempt to breast-feed their infants is less than 50%- Do not put infants through low-fat, low-calorie diets (health risk)Development of the Brain Central Nervous System constitutes the most complicated physical structure inthe body. All aspects of development are mediated either directly or indirectly by centralnervous system development Structure of the Brain - Brain structure emerges in the prenatal stage - During prenatal stage 250,000 new nerve cells add each minute, resulting in 100 billion nerve cells in a newborn- Brain structure continues to evolve through first 10 years of life Neurons: highly complex biological structures than conduct electrochemical impulses - Neurons line up into sequences or NERVE PATHWAYS that conduct impulses throughout the body Synapse: microscopic gap forming when the axon of one cell butts up against the dendrite of another cell Neurotransmitters: impulses transmitted across the synapse (from cell to cell) by these chemicals Myelination: axons develop an insulating, fatty coating that improves the efficiency of nerve impulse transmission. Continues throughout childhood, adolescence and adulthood Synaptogenesis: synapses begin to develop in very large numbers prenatally and continue to increase inextraordinarily large numbers through the first 3 years of life - Highest level of synaptic density in the third year of life- At this point in development (prenatal stage) the brain contains 1000 trillion synapses, 50% more than the adult brain- During prenatal stage of development the essential “architecture” of the brain is formed- Late in gestation, nerve cells begin to fire, sending impulses through various pathways in developing brain, organizing brain function. - After birth, brain is bombarded by pattern stimulation particularly through routine interaction with caregivers. Plasticity of the Brain - The fundamental structure of the nervous system is designed to manage the storage and transfer of all of the information necessary to support the biological function of bodily systems and the psychological functions of sensations, perception, learning and intelligence. - The nervous system is an evolving system of circuits that is designed with more potential capacity than it is ever likely to need. Plasticity: if one part of the nervous system becomes damaged or unable to function Hemispherectomy: the radical removal of half of a child’s brain in the treatment of extreme cases of brain seizures. (Demonstration of plasticity) - After the second year, the rate of production of new synapses levels decreases and they disappear. - Elimination process is based on a simple neurological principle: pathways that get used repeatedly survive; those that go unused disappear. “Use it or Lose it” Principle: results in leveling off of the number of synapses from the end of the second yearthrough approximately the tenth year or around the time kids graduate elementary school- The greater the variation and organization of incoming stimuli, the greater number of pathways that survive Pruning: synapses and cells that are not stimulated are eliminated through this massive and continuing destructive process- Pruning happens in years of adolescence, adult brain contains 50% of synapses that were in the brain of a three-year-old. - Early experience triggers genetic mechanisms that influence every aspect of brain development: proliferations of neurons, formation of synapses, migration of neurons, differentiation offunctional areas of the brain, pruning away unused cell and synapses to consolidate adaptive capabilities of brain - Children who experience more varied, organized, repetitious and more consistently challenging interaction will better developPerceptual Development Methods of Study - Sensation: refers to the ability to passively receive and register information concerning internal and external events and to transmit that information to the central nervous system - Perception: refers to the infants active searching for information and the
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