8 You grow a whole new organ
Credit: Image from Gray’s Anatomy (1918); Public DomainIt’s not just a baby-to-be developing in the womb; pregnant women are also growing a whole new organ. The placenta is the only transient organ in the human body. It starts to form when the fertilized egg, at this point a multicellular blastocyst, implants in the uterine wall about a week after conception. The outer layer of the blastocyst, called the trophoblast, develops into what will be the bulk of the placenta.
Once the placenta is established, its job is to form a porous barrier between mom’s and baby’s blood. Maternal vessels seep nutrients and oxygen into spaces called intervillous spaces in the placenta, where fetal vessels pick up these necessities to deliver to the developing fetus via the umbilical. The fetus rids itself of waste in the same way.
The placenta has another, lesser-known part to play in its role as temporary organ. This one-pound (2.2-kilogram) dark-red disk is also an endocrine organ, meaning it excretes hormones. These hormones, from human chorionic gonadotropin (hCG, the hormone detected in pregnancy tests) to estrogen and progesterone, are crucial for maintaining the pregnancy and preparing the mammary glands for nursing.
http://www.livescience.com/16937-body-pregnancy.html Blossoming Body: 8 Odd Changes That Happen During Pregnancy
wyandotcountyrightolife 