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.
1 In the placenta, the mother's blood brings nutrients to the fetal blood and carries away waste products. 2  This happens through diffusion across the placental membrane. 3  The umbilical cord, containing the umbilical vein and arteries, connects the fetus to the placenta of the mother.he ductus arteriosus connects the pulmonary artery to the aorta, the ductus venosus connects the umbilical vein to the inferior vena cava, and the foramen ovale allows blood to go directly from the right atrium to the left atrium. The pathway of blood through the fetal circulation system is as follows: