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Chapter 3

PSYC 2290 Chapter 3: Chap 3_Prenatal Developmental

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PSYC 2290
Jocelyn B.Proulx

Child Development Chapter3 Prenatal Developmental, Birth and the Newborn https://quizlet.com/155956768/developmental-psychology-prenatal-development-flash-cards/ - some of the most memorable experiences are associated with pregnancy and child birth - Prenatal devp : The changes that transform a fertilized egg into a newborn human - It takes 38 weeks - divided into 3 stages : 1. the period of the zygote 2. the period of embryo 3. the period of fetus  Period of the Zygote (weeks 1 - 2) - begins with fertilization - lasts abt 2 week - It ends when the fertilized egg called a zygote, implants itself in the wall of the uterus - during these 2 weeks, zygote grows rapidly through cell division - travels along fallopian tube toward the uterus - Within hours, Zygote divides for the first time. After that, every 12hrs - sometimes, it divides into 2 clusters, which then develop into identical twins - Fraternal twins : two eggs released at same time and each is fertilized by a diff sperm cell - however many times a zygote splits, the resulting cell masses then continue to devp individually (eg : Dionne sisters) - After that four days, the zygote comprises of 100 cells, resembling a hollow ball called Blastocyst - by the end of 1st week after conception, Zygote reaches uterus - next step is Implantation : the blastocyst burrows into the uterine wall and establishes with the mother's blood vessels - it takes abt a week. - hormonal changes happen and menstruation stops - A small cluster of cells near the centre of the blastocyst called Germ disc, eventually develops into a baby - The layer of cell closest to the uterus becomes the placenta, a structure for exchanging nutrients and wastes btwn the mother and the developing organism - Implantation and differentiation of cells mark the end of the period of the zygote  Period of the Embryo ( Weeks 3 - 8 ) - once the blastocyst is completely embedded in the uterine wall, it is called an Embryo - during this period, Body structures and intrnal organs develop - at the beginning, 3 layers from the embryo 1. The outer layer or Ectoderm will become the hair, outer layer of skin, nervous system 2. The middle layer or Mesoderm will form muscles, bones and circulatory system 3. The inner layer or Endoderm will form the digestive system and the lungs - can see the diff when we compare a 3 week old embryo to 8 week old embryo - in 3 week, embryo is abt 2mm long - by 8th week, we can see eye, jaw,an arm and a leg - heart will be beating nearly for a month by then - The embryo rests in an amniotic sac, which is filled amniotic fluid that cushions the embryo and maintains a constant temp - The embryo is linked to the mother : ➢ Umbilical cord : houses blood vessels that join the embryo to the placenta ➢ the blood flows through villi fingerlike projections from the umbilical blood vessels Child Development Chapter3 - allows nutrients, oxygen, vitamins etc to be exchanged btwn mother and embryo  Period of the Fetus ( Weeks 9 - 38) - final and longest phase - at abt 4 months, the fetus weighs abt 110 - 225 gms - can gain 3 - 4 kgs more - nervous, respiratory and digestive system • At 4 weeks, a flat set of cells curl to form a tube. One end tube swells to form brain and the rest to spinal cord • all regions of brain grow particularly cerebral cortex • near the end of the embryonic period, male embryos develop testes and females : ovaries • In 3rd month, the testes in male fetus secrete a hormone that causes the cells to become a penis & scrotum • That hormone is absent in female fetus, so the same cell becomes a vagina and labia • during 5th & 6th months : eyebrows, eyelashes and scalp hair emerge • The skin thickens and is covered with a thick and greasy substanc called Vernix, which protects the fetus during its long bath in amniotic fluid • by 6th month, heart rates varies acc to physiological stress • greater heart rate variabilty is a sign that nervous system is responding well to environment changes - by 22 - 28 weeks, all the systems function well and the fetus can be born : Age of viability - babies born early have trouble breathing cos their lungs are still not mature - also lack regulating temp as they lack the fatty layer than happens in the 8th month ❖ Fetal behavior : - when active, the fetus moves once a minute - The fetus can hear mother's heartbeat and food being digested also hear everything spoken to him/her - can taste - can remember these sensory experiences later - for better environment : - Visit doctor for regualr checkups - eat healthy - stop drinking alcohol and beverages - exercise theoughout pregnancy - get enough rest  General Risk Factors : ❖ Nutrition: - mother is the child's sole source of nutrition - pregnant women should increase 10 - 20% calorie intake - must gain aroung 11 - 16kgs (underweight : 18kgs : : overweight : atleast 7kgs) - folic acid, one of the vitaminB is very imp for the nervous system to devp properly - when mothers do not consume adequate amts of folic acid, their babies are at risk for spina bifida : a disorder in which the embryo's neural tube does not close properly during the 1st month of pregnancy - ( cos the neural tube develops into brain and spinal cord, it may lead to permanent damage) - when a pregnant women doesn't consume all the nutrients, the infant is born prematurely and is underweight ❖ Stress : - women experiencing anxiety during pregnacny, give birth early / have underweight babies - infants will have attention & behavioral problems - when she experiences stress, her body secretes hormones that reduce the flow of oxygen to the fetus Child Development Chapter3 - can weaken her immune system - are more likely to drink/smoke and less likely to eat, sleep and exercise properly ❖ Mother's age : - teenage mothers usually do not get proper prenatal care - and their kids will not do well in school & have behavioral problems - problems : - social influence : events tht make it hard for her to provide a positive environment for her child's devp - social slection : some teenage girls are more likely to become pregnant than others, the same factors dause grils to become pregnant ,ay put their children at risk - Women is their 20's are twice as fertile as women in their 30's - past 35yrs: miscarriage and still birth risks - women in 40's are more likely to give birth to kids with down syndrome - through devp of science, women after menopause can also conceive. - the older the father, more likely their kid suffered from Autism/ down syndrome etc  Teratogens : Diseases , drugs & environmental hazards - a sedative called Thalidomide was prescribed for morning sickness. It is a powerful teratogen, an agent that causes abnormal prenatal devp ❖ Diseases : - cold and flu dont effect developing babies - some of the diseases pass from the mother through the placenta to attack the embryo or the fetus directly : Cytomegalovirus, rubella and syphilis - other diseases attack at birth - the virus is present at lining of the birth canal and baby is affect during the birth process - AIDS is transmitted through placenta as well as birth canal - medication may help the women but can't guarantee that the baby wont be harmed ❖ Drugs : - smoking women : miscarriage / smaller babies with low weight - children would show lang impairment, attn, cog skills and behavioral problems - second hand smokers can also be harmed - pregnant ladies who consume alcohol can give birth to babies with fetal alcohol spectrum disorder (FASD) - heavy drinkers will give birth to babies with Fetal alcohol syndrome (FAS) - 1 in 100 children suffer from FAS - have heart prob and atypical facial features - ALcohol-related neurodevelopmental dis : - normal appearence but deficits in attn, memory and intelligence - eye movements can be used to distinguish children suffering from FAS ❖ Environmental Hazards : - ppl are exposed to toxins in food they eat, fluids they drink and air they breathe - chemicals associated with industrial waste : teratorgens - can cause severe damage to fetus - leads can cause cog deficiits, schizophrenia - cell phones uses - risk for behavioral probs  How teratogens influence Prenatal devp : - The impact of the teratogen depends on the genotype of the organisms - substances may be harmful to one person and not to the other - the impact changes over the course of prenatal devp - during zygote, exposre to teratogens results in abortion Child Development Chapter3 - during embryo - major body defetcs - during fetus - minor defects / fuctions improperly - each teratogrn effects a specific aspect of prenatal devp - the impact depends on dose - damage by teratogens are not detectable during birth  Prenatal Diagnoses and Treatment : - Ultrasound procedure : using sound waves to generate a picture of the fetus - 3D and 4D ultrasounds exist now - can examine facial expressions and also simple physical assessment of the fetus - can be used after 4 - 5 weeks of pregnancy - it is used to predict the date of conception so that the due date will be known - can detect twins - beginning abt 20weeks, it can detect sex of the child - In amniocentesis, a needle is inserted through the mother's abdomen to obtain a sample of amnitoic fluid that surrounds the fetus - performed after 16 weeks of pregnancy - ultrasound is used to guide the needle i
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