Human Development

Human development is a complicated and dynamic process that is almost beyond belief. During the first eight weeks the developing human is called an embryo, while from week nine onward it is called a fetus.


The plancenta (and associated sturctures) is the primary site of nutrient and gas exhange between the mother and her baby.


During week one, fertilization, cleavage, and implantation occurs.

Durng week two, the embryo forms a bilaminar disc.

During week three, a trilaminar disc forms and three dimensions start to appear.

During weeks four to eight, all major organs and systems form.

During weeks nine to forty, or the fetal period, structures become refined during a period of phenomenal growth.


Systems Development





Resources and References