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 composed of both maternal tissue and tissue derived from the embryo. The chorion is the embryonic-derived portion of the placenta. It is composed of fetal blood vessels and trophoblasts which are organized into finger-like structures called chorionic villi.et's review. The placenta is the composite structure of embryonic and maternal tissues that supplies nutrients to the developing embryo. The placenta serves three main functions: 1  Attach the fetus to the uterine wall. 2  Provide nutrients to the fetus.