PSYC 2450 Chapter Notes - Chapter 4: Sickle-Cell Disease, Radiography, Fetal Surgery

• School: University of Guelph
• Department: Psychology
• Course: PSYC 2450
• Professor: Heidi Bailey

Document Summary

Changes that transform a ferilized egg into a newborn human make up prenatal development. Takes a average of 38 weeks divided into three stages: period of zygote, period of embryo, period of fetus. Begins with ferilizaion and lasts about 2 weeks. Ends when the ferilized egg, zygote, implants itself into the wall of the uterus. During these two weeks, the zygote grows rapidly through cell divison and travels down the fallopian tube toward the uterus. Zygote divides within hours and then divides every 12 hours. Occasionally, zygote separates into two common clusters that develop into idenical twins. Fraternal twins occur when two eggs are released and each is ferilized by a diferent sperm. Ater 4 days, the zygote consists of about 100 cells and resembles a hollow blast blastocyst. By the end of the irst week, the zygote reaches the uterus and the blastocyst burrows into the uterine wall and establishes connecions with the mother"s blood vessels.