HDFS 230 1st Edition Lecture 6Prenatal DevelopmentStages:1.) Zygote- 2 weeks -Fertilization-Implantation-Start of Placenta-Rapid cell division/ differentiation2.) Embryo- 6 weeks-Basic body structures form-Heart begins to beat3.) Fetal stage- 30 weeks-Growth and maturation-Brain developmentConception- “magic”-FertilizationVideo: Life’s Greatest Miracle(watched throughout lecture, goes through stages)-60 percent of sperm is less than perfect- Many barriers that sperm must over passGerminal Period-Zygote begins duplication and division within hours of conception-Rapid growth evident-Development of the placenta-Organ that surrounds embryo/ attaches to the uterus-Sustains life via umbilical cord (nourishes and discards waste)Implantation (~10 days after conception)-Burrows into the placenta that lines the uterusVideo-50 percent of all fertilized egg fail to developEmbryonic Period- 3 to 8 weeks after conception-Primitive streak- appears down the middle of the cell mass (shrimp)-Becomes the neural tube that later forms the CNS-Basic forms of the body structures developThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.-Head takes shape-Eyes, ears, mouth, and nose form-Heart begins to pulsate-Extremities develop and webbed fingers and toes separateVideo-Fetal Period- 9 to birth week-Principals of fetal growth-Proximodistal-Middle to outside-Cephalocaudal-Head to feetMass to specific- large structures and movements appear before finerEx: move arms before fingersFetal brain development:-Cortex is not fully mature at birth-Brain at birth is far bigger than any other part of the baby-Genitals form and sex hormones cause differences in fetal organizationAge of viability:-Age at which a preterm newborn may survive outside uterus if medical care was available-22 weeks after conception-Brain is not yet able to regulate body functionsEx: