BIOL 121 Lecture Notes - Lecture 13: Corpus Luteum, Umbilical Cord, Human Chorionic Gonadotropin
Document Summary
Progesterone is essential for pregnancy to be maintained initially corpus luteum supplies progesterone to the body. Lifespan is extended by release of human chorionic gonadotropin (hcg) by trophablast cells until placenta assumes this role at around 10 weeks of gestation. Overtime trophoblast cells change when they invade they create spaces that are opened to mom"s blood vessels. Babies blood in vessels they form by trophoblast cells, called chronic villi (blood never mixes) Mom gives baby nutrients, oxygen, hormones, in exchange baby gives mom co2 to exhale and excrete other waste. Estrogen: high estrogen develops muscle in uterus. Hcg is hormone detected by pregnancy test body only produces it when pregnant, made by cells that form the placenta which nourishes egg after it has been fertilized and becomes attached to uterine wall. Major function of nervous system is to maintain constancy of internal environment homestasis.
