What characterizes the germinal period in prenatal development?

The germinal period in prenatal development is primarily characterized by rapid cell division and the beginning of cell differentiation. This stage occurs from conception until about two weeks into the pregnancy. During this time, the fertilized egg, or zygote, undergoes several rounds of cell division as it travels down the fallopian tube and eventually implants itself into the uterine lining.

Cell differentiation begins during this period as the cells start to take on specific roles that will eventually lead to the formation of various tissues and organs. This early process is crucial as it sets the foundation for the future growth and development of the embryo.

While the formation of major organs, fetal growth, and the placenta are all important milestones in prenatal development, they occur in subsequent stages—organ development typically happens during the embryonic period, and fetal growth and maturation occur during the fetal period. Hence, understanding these stages helps clarify why rapid cell division and differentiation are defining features of the germinal period.