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.
The allantois is a sac-like structure that forms near the posterior of the embryo. It eventually forms into the umbilical cord, but only in placental animals. The umbilical cord is how the offspring gets gases and nutrients. This is exactly what the allantois is used for.