Chapter 1. Prenatal Development

Short Description

The story of life begins in the womb, where much of whom we will become when we enter the world is influenced.

Long Description

While it is estimated that over half of all zygotes never reach the implantation stage, which occurs within the first two weeks after conception, successful implantation is typically followed by normal development. But, genetic and environmental factors can sometimes cause deviations in the developmental process. This program provides an overview of the three main stages of prenatal development while highlighting the major events in each stage. Students will gain an understanding as to why psychologists include prenatal development in their course of study on the human mind and behavior.

Implantation occurs during the germination stage—the earliest stage of prenatal development. Between the second and eighth weeks, the mass of cells, now called an embryo, starts to become a human being. The neural tube, which will later become the spinal cord and central nervous system, forms and sex differentiation begins. By the eighth week, says Janet DiPietro, the embryo has formed 95% of the basic organs and body parts. The last three months of gestation are marked by dramatic growth, especially in the brain. In the weeks prior to birth, the digestive, respiratory, and nervous systems mature and prepare the fetus for life outside of the womb.

The next section of the program focuses on how genetic and environmental factors influence prenatal development. Epigenetics refers to the interaction between the environment and genes. The placenta enables maternal blood to pass oxygen and nutrients to the developing fetus while taking waste, like carbon dioxide, from fetus to be disposed of. Teratogens, like alcohol and cigarette smoke, which are also carried across the placenta and through the maternal bloodstream to the fetus, can damage the process of development.

DiPietro points out that the primary reason the human gestational period is so long is so the developing brain can be prepared to absorb the immense amount of information it will receive, especially in the early years of life.

Questions