EXAM 3: 11/25/14chapter 11: human development across the life span-development: the sequence of age-related changes that occur as a person progresses from conception to death•biological and behavioral changesprogress before birth: prenatal development -development begins with conception, which occurs when fertilization creates a zygote-zygote: a one-celled organism formed by the union of a sperm and an egg•chromosomes within the nucleus of cells carry enduring messages from your parents•many genes are found in each chromosome; genes are the functional units in hereditary transmission (carry details of your hereditary blueprints)-prenatal period: extends from conception to birth, usually encompassing 9 months of pregnancy•remarkably rapid rate of development-The Course of Prenatal Development•Germinal stage-germinal stage: the first phase of prenatal development, encompassing the first two weeks after conception-first zygote is created through fertilization, then rapid cell division begins and mass of cells travels along fallopian tubes to uterine cavity, implant in uterine wall•during implantation the placenta begins to form-placenta: a structure that allows oxygen and nutrients to pass into the fetus from the mother’s bloodstream and bodily wastes to pass out to the mother•thin membrane blocks the passage of blood cells, keeps the fetal and maternal bloodstreams separate•Embryonic stage-embryonic stage: the second stage of prenatal development lasting from two weeks until the end of the second month-most of the vital organs and bodily systems begin to form (now called embryo)•heart, brain, and spine emerge; arms, hands, legs, feet, fingers, toes, eyes, and earn discernible1EXAM 3: 11/25/14-period of great vulnerability because if anything interferes with normal development here, the effects can be devastating (miscarriages, structural birth defects)•Fetal stage-fetal stage: third stage in prenatal development last from two months through birth-first two months - rapid bodily growth, muscles and bones form (now called fetus)•physical movements, organs begin to function-final three months - brain cells multiply, fat provides insulation, respiratory and digestive systems mature•threshold of viability: the age at which a baby can survive in the event of a premature birth (23-26 weeks)•many premature infants born near the threshold of viability experience developmental problems2EXAM 3: 11/25/14-Environmental Factors and Prenatal Development-the developing organism and its mother are linked through the placenta so a mother’s eating habits, drug use, illnesses, nutrition, and emotions can affect prenatal development-teratogens: any external agents, such as drugs or viruses, that can harm an embryo or fetus•Maternal Drug Use-most drugs consumed by a pregnant woman can pass through the membranes of the placenta-sedatives, narcotics, and cocaine are the most dangerous “recreational” drugs•babies of heroine addicts are born addicted to narcotics and have an increased risk of early death due to prematurity, birth defects, respiratory difficulties, and issues associated to their addiction•prenatal exposure to cocaine is associated with increased risk of birth complications and cognitive deficits apparent in childhood-fetal alcohol syndrome (FAS): a collection of congenital (inborn) problems associated with excessive alcohol use during pregnancy•microcephaly (small heart), heart defects, irritability, hyperactivity, delayed mental and motor development•most common known case of mental retardation•studies show that increased alcohol intake was associated with an elevated risk for deficits of IQ, motor skills, attention span; increased impulsive, antisocial, delinquent behavior-smoking appears to increase a mother’s risk for miscarriage, stillbirth, and prematurity in the newborn’s risk for sudden infant death syndrome•slower-than-avg. cognitive development, attention deficits, hyperactivity, conduct problems (can’t point out causal relationships)•Maternal Illness and Exposure to Toxins-the fetus is defenseless against infections because its immune system matures late in the prenatal period-measles, rubella, syphilis, chicken pox hazardous to the fetus•the nature of any damage from these illnesses depends in part on when the mother contracts the illness•HIV virus can be transmitted by pregnant women to their offspring prenatally through the placenta, during delivery, or through breastfeeding3EXAM 3: 11/25/14-babies in the womb are exposed to a variety of environmental toxins•air pollution - impairment of cognitive development•chems. in flame-retardant materials - slower mental and physical development•Maternal Nutrition and Emotions-malnutrition increases the risk of birth complications and neurological defects for the newborn•major problems in underdeveloped nations where food shortages are common-impact of moderate malnutrition is difficult to gauge because it’s often confounded with other risk factors associated with poverty (drug abuse, ltd. access to healthcare)-recent studies suggest that maternal emotions can have an impact on prenatal development•anxiety and depression associated with increased prevalence of various behavioral probs. in offspring•mothers’ emotional reactions to stressful events can disrupt the delicate hormonal balance that fosters healthy prenatal development•Fetal Origins of Disease-recently researchers have explored the links between prenatal factors and adults’ physical and mental health-events during prenatal development can “program” the fetal brain in ways that influence the person’s vulnerability to various types of illness decades later•malnutrition - schizophrenia•low birth weight - increased risk of heart diseaseSummaryPrenatal development proceeds through the germinal (first 2 weeks_, embryonic (2 weeks-2 months), and fetal stages (2 months-birth) as the zygote is differentiated into a human organism. The embryonic stage is a period of great vulnerability, as most physiological structures are being formed. The fetal stage brings rapid growth as physiological systems mature.Maternal use of illicit drugs can be dangerous to the unborn child. Even normal social drinking and routine tobacco use can be very hazardous during prenatal development. A variety of maternal illnesses can interfere with prenatal development. Maternal malnutrition during the prenatal
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