Psychology 2410A/B Chapter Notes - Chapter 3: Infant Mortality, Neural Tube, Prenatal Development
Document Summary
Prenatal development can be divided into three periods: germinal: 1st trimester. The period of prenatal development that takes place in the first two weeks after conception. It includes the creation of the zygote, continued cell division, and the attachment of the zygote to the uterine wall. The group of cells at this point in development are called: Blastocyst: the inner layer of cells that develops during the germinal period. Trophoblast: the outer layer of cells that develops in the germinal period. These cells provide nutrition and support for the embryo. Implantation occurs 11-15 days after conception: embryonic: 1st trimester. The period of prenatal development that occurs from two to eight weeks after conception. During the embryonic period, the rate of cell differentiation intensifies, support systems for the cells form, and organs appears. The mass of cells previously called the blastocyst, now attached to the uterine wall, is now called an embryo which has three layers of cell.