PRE 305 1st Edition Lecture 5 Outline of Last Lecture I. Nature and nurtureA. Nature and nurture in physical developmentOutline of Current Lecture I. Prenatal development and birthA. Periods of prenatal developmentB. Patterns of developmentC. FertilizationD. What affects prenatal developmentE. Birth: The mother’s experienceF. Birth: The child’s experience Current LecturePeriods 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 exposureo Amount of exposureo Length of exposureo Individual differences- Prenatal medical care Birth: The mother’s experience- Stages of labor: 1. Uterine contractions2. Mother pushing the baby out3. Placenta is expelled- Role of oxytocin: happy and contented feeling, milk coming in.- Importance of supportBirth: The child’s experience- Adrenaline and other stress hormones are