pregnancy. It is divided into a preembryonic phase , in which the three germinal layers arise, and into the embryonic phase proper, in which the embryonic organ anlagen arises. Fetal Phase • Briefly describe the main features of this phase of development. Officially begins after the tenth week of pregnancy. Prior to this, the developing child is considered an embryo. Before the tenth week is reached, many physiological developments have already happened. By this point, the embryo has started the process of developing heart and nervous tissue, has started developing a gastrointestinal tract, and has distinguishable limbs Summary • Now that you have viewed the entire sequence of prenatal development, what do you think are the most important themes of development during these 38 weeks? ● growth in body size, from a single cell to a full-size baby; ● shift in proportions, as the lower portion of the body begins to catch up with the early development of the head ● functional development of the various organ systems, as each system gradually begins working and then becomes more efficient as the fetus reaches viability and then prepares for birth.
- Fall '18
- Makoto Ogura
- Embryo, 2 weeks, 8 weeks, 38 weeks