PRE 305 1st Edition Lecture 5 Outline of Last Lecture I Nature and nurture A Nature and nurture in physical development Outline of Current Lecture I Prenatal development and birth A Periods of prenatal development B Patterns of development C Fertilization D What affects prenatal development E Birth The mother s experience F Birth The child s experience Current Lecture Periods of prenatal development Germinal stage 0 2 weeks Conception to implantation Zygote s cells are dividing while traveling down the fallopian tubes Zygote produces chemicals that help to protect it from the mother s immune system HCG is one such chemical that also shows up in a pregnancy test Embryonic stage 3 8 weeks Processes of cell division migration differentiation and death Called an embryo Role of hormones hormones will develop to determine if male or female Role of placenta filter between the mother s body and the embryo Fetal stage 9 40 weeks Cell now called a fetus Starts the fetal stage at an inch long Development of organs and limbs Fetal movement kicking thumb sucking swallowing hiccupping have active times of day and restful times of day Fetal learning can start learning tastes and sounds Patterns of development Cephalocaudal head to feet development head more developed than other parts of body Proximodistal development occurs in chest in middle part of the body Fertilization Once the egg is fertilized the egg is referred to as a zygote the zygote then travels down the fallopian tube to the uterus What affects prenatal development Maternal nutrition maternal food deprivation can lead to premature birth miscarriage and later consequences for child Good nutrition is associated with more positive outcomes for child later in life Maternal exercise positive outcomes for both mother and child Less pain during labor etc Maternal stress high levels of stress associated with miscarriage prematurity and low birth weight Teratogens diseases drugs environmental toxins 1 Impact of teratogens o Timing of exposure o Amount of exposure o Length of exposure o Individual differences Prenatal medical care Birth The mother s experience Stages of labor 1 Uterine contractions 2 Mother pushing the baby out 3 Placenta is expelled Role of oxytocin happy and contented feeling milk coming in Importance of support Birth The child s experience Adrenaline and other stress hormones are released