PSYC 304 Chapter Notes - Chapter 3: Vernix Caseosa, Human Tooth Development, Teratology
Document Summary
A woman can conceive for only a short window of time each month. Uterine lining thickens in preparation for a fertilized ovum, but if fertilization does not occur, the lining is shed through menstruation about two weeks after ovulation. During ejaculation, about 360 million sperm are released, covered in a protective fluid called semen. 300 actually reach the ovum if it is present. In the presence of sperm, the ovum exudes a chemical signal to draw it closer. Germinal period (first two weeks after conception) Zygote begins cell division and travels to the uterus. Cell differentiation begins 72 hours after fertilization. Implantation starts at day 6 and is done by day 11. Embryonic period (third to eighth week after conception) All of the organs and major body systems form. Days 26 and 27: arm buds start to appear. Days 28 through 30: leg buds start to appear. Webbed fingers and toes at seventh week, separate completely by eighth week.
