How does the embryo survive after it implants in the lining of the uterus?
The embryo starts in the fallopian tube and migrates to the lining of the uterus within a few days of fertilization. Along the way it uses energy and nutrients to do what it needs to do to live and grow and gets rid of metabolic waste that can be toxic if allowed to build up. This may be simple enough for an organism consisting of dozens of cells that’s floating within the fluid of the uterine cavity, but the embryo is destined to become a newborn baby with trillions of cells that have developed into several complex organ systems. This means that once it implants in the lining of the uterus it has to find a more permanent source of energy and nutrients while getting rid of toxic chemicals for it to survive and develop within the womb over the next several months.
The outer tissue of the embryo sends out enzymes to breakdown the lining of the uterus which allows it to implant. The embryo then attaches to this tissue and burrows in further. It then sends out more enzymes to cause more breakdown of the uterine lining including its blood vessels. As this takes place the outer tissue of the embryo develops and joins with the broken down lining of the uterus to form something called the placenta.
The placenta is a specialized organ that allows the blood of the mother and the developing fetus to come very close to each other but not intermingle. The blood connection between them comes from the arteries in the lining of the uterus and the baby’s umbilical cord. Due to this set up chemicals can move back and forth between the mother’s and the baby’s circulation. In this way the mother can send her child the oxygen and nutrients it needs to live, grow and develop while taking away metabolic waste.
But besides this the placenta has another very important role. The last article detailed how the mother’s corpus luteum (the tissue left over in the ovary after it releases an egg) has to keep sending out estrogen and lots of progesterone to prepare the lining of the uterus to receive the embryo. Since the corpus luteum usually only lives ten to fourteen days the embryo has to send out hCG (human chorionic gonadotropin) to tell it to hang around and keep working for several more weeks otherwise a miscarriage would take place.
Within a few weeks the placenta takes over the job of the corpus luteum by sending out enough estrogen and progesterone to keep the lining of the uterus from shedding. This allows it to house the placenta and keep the pregnancy going to full term about 38 weeks later. So one can see that although the father provides the sperm and the mother provides the egg and womb, the embryo along with the placenta it helps to form has to do a lot of work of its own to keep itself alive.
Three Questions for Mr. Darwin
- Once the embryo implants how does it know that it needs to send out more enzymes to breakdown the uterine lining and where did the information come from to make them?
- How did life anticipate the need for and where did the information come from to make all the parts of the placenta?
- How does your theory take into account where the information came from to allow the placenta to make the two sex hormones needed to supplement the uterine lining so the fetus can develop into a new born baby?
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Howard Glicksman M. D. graduated from the University of Toronto in 1978. He practiced primary care medicine for almost 25 yrs in Oakville, Ontario and Spring Hill, Florida. He now practices palliative medicine for a Hospice organization in his community. He has a special interest in how the ethos of our culture has been influenced by modern science’s understanding and promotion of what it means to be a human being.
Copyright 2019 Dr. Howard Glicksman. All rights reserved. International copyright secured.
