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 placenta is connected to the fetus by an umbilical cord. Inside the cord are two arteries and a vein; both arteries are referred to as umbilical arteries. The two arteries wrap around the umbilical vein which carries oxygenated blood and nutrients from the placenta to the fetus. Once the oxygen and nutrients have been used, the umbilical artery transfers the deoxygenated blood and waste from the fetus back to the placenta.