Embryonic Development

Embryonic development progresses rapidly, with the initial cell division occurring within hours of fertilization. In humans, by the third week, the heart begins to beat, and by eight weeks, most major organs and structures have started to form.

The process is highly synchronized, with genes and molecular signals guiding the differentiation and growth of cells into tissues and organs. This quick pace is crucial, as each stage of development depends on precise timing to ensure that the body forms correctly, with the entire process of major organ formation typically completed by the end of the first trimester.