PSYC 4070 Chapter : Dev Psyc Chapter 4
Document Summary
Prenatal development is often divided into three main periods: germinal period first two weeks of prenatal development. The one-cell zygote, traveling slowly down the fallopian tube towards the uterus, begins to duplicate and multiply. The early cells take on distinct characteristics and gravitate towards specific locations, foreshadowing the types of cells they will become. After about one week, the multiplying cells will separate into two distinct masses. The outer cells will form a shell that will become a placenta (the organ that surrounds and protects the developing baby), and the inner cells form a nucleus that will become the embryo. The outer cells must achieve implantation that is, to embed themselves in the nurturing lining of the uterus. This is far from automatic; about 60% of natural conceptions and 70% of in vitro conceptions do no implant: embryonic period three to eight weeks.
