One of the most remarkable examples of cell communication is the fight or flight response. body handle extraordinary situations. responses involved in the fight or flight response. place in the movie. 0:16 An environmental signal travels into the brain. a nerve impulse to the hypothalamus (not shown).
Umbilical cord. In placental mammals, the umbilical cord (also called the navel string, birth cord or funiculus umbilicalis) is a conduit between the developing embryo or fetus and the placenta.
Formation of Umbilical Cord. When the placenta forms, the embryo and placenta connect through a stalk surrounded by the primitive umbilical ring. As the embryo grows and develops into a fetus, the stalk also grows while developing two arteries and a vein.