Embryonaalivaihe

Embryonaalivaihe refers to the early stages of development in a multicellular organism, typically from fertilization or the beginning of development until the organism takes on a recognizable form. This period is characterized by rapid cell division, differentiation, and the formation of basic body structures. In humans and other vertebrates, the embryonaalivaihe follows the zygote stage and is a critical period where major organ systems begin to develop. This includes the formation of the three primary germ layers: ectoderm, mesoderm, and endoderm, which will give rise to all the tissues and organs of the body.

The duration of the embryonaalivaihe varies significantly across species. For humans, this stage is generally considered to last for the first eight weeks after fertilization. During this time, the embryo is particularly vulnerable to external factors such as toxins and radiation, which can cause developmental abnormalities. Following the embryonaalivaihe, the developing organism enters the fetal stage, where growth and maturation of already formed organs and structures become the primary focus. The successful completion of the embryonaalivaihe is essential for the subsequent healthy development of the organism.