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Many people have mistaken ideas about how a growing embryo eats and breathes in the uterus.
From the earliest stages of its development, the growing embryo requires nutrition and oxygen, and a disposal system for the waste products of its own metabolism. All of this is accomplished by the placenta, which allows the growing embryo to eat and breathe while in the mother's uterus.
To get some perspective on how the placenta began, let's go back to Day 8. This hollow ball of cells moving through the uterus is the blastocyst, searching for an implantation site. Here you see its outer layer beginning to extend out and implant in the uterine lining, searching for the uterine blood vessels that would nourish it throughout the pregnancy.
As it went deeper, a single layer of cells from the mother's uterine lining surrounded it, so that it would be protected from harm. On Day 9, as it grew larger and more complex, the blastocyst became an embryo. Here it's about the size of a pinhead.
Also on Day 9, the outer layer of the embryo developed spaces called lacunae. The lacunae filled up with blood from the mother's uterine lining.
On Day 13, small projections from the embryo's chorionic layer reached out into the uterine lining. The chorionic layer is one of the membranes that surround the embryo and help it implant.
On Days 15 through 21, blood vessels began to form beneath this chorionic layer.
Around Day 21, the embryo's blood stream and the mother's blood stream were in such close contact that nutrients and oxygen could cross from mother to embryo. This was how the embryo first got its food and air from the mother, and technically this is when the placenta began to function.
Let's magnify this area so you can see what we're talking about. Here you see a vein and an artery from the embryo in close contact with the blood in the mother's uterine lining. Inside the blood vessels, you can also see red blood cells, which carry oxygen.
The two blood streams are separated by a thin collection of tissues in the placenta called the blood barrier. This barrier permits small particles like nutrients and oxygen to pass from the mother to the embryo, (pause) and allows waste products to pass from the embryo back to the mother. The blood barrier also prevents many large or potentially harmful particles from entering the embryo's blood stream. Notice that the red blood cells do not cross from the mother's blood stream to the embryo's.
You may be wondering how a mother's blood cells could be harmful to her growing baby, and why it's important to keep the two blood streams separate. If the mother's blood type is RH negative, and her embryo's blood type is RH positive, then the mother's antibodies would treat the embryo as an invading foreign organism, and try to destroy it.
Now you can see why the placenta and its blood barrier are important for supplying the growing embryo with nutrition and oxygen, removing its waste products, and preventing harmful substances from getting into its blood stream.
Reviewed ByReview Date: 09/16/2008
Dan Sacks MD, FACOG, Obstetrics & Gynecology in Private Practice, West Palm Beach, FL. Review provided by VeriMed Healthcare Network.
What else can I help you with?
What occurs first labor cleavage implantation gastrulation or formation of placenta?
cleavage->gastrulation->implantation->formation of placenta->first labor
Does endometrium participate in the formation of the placenta?
No, the endometrium does not directly participate in the formation of the placenta. The placenta is formed from the embryonic tissue (trophoblast) and the maternal tissue (decidua) lining the uterus, not from the endometrium.
What viruses play a critical part in the formation of the placenta in humans?
None.
When formation of a placenta signals the onset of?
The formation of a placenta signals the onset of pregnancy in mammals. This structure facilitates the exchange of nutrients, gases, and waste between the mother and the developing fetus. Additionally, the placenta plays a crucial role in hormone production, which helps maintain the pregnancy and supports fetal development. Its formation marks a critical transition from embryo development to a more complex stage of gestation.
Which foetal membrane takes part in the formation of placenta?
placenta is a complex structure formed by the process of trophoblastic cells (chorionicfondosum)and part of uterine endometrium called decidua basalis
Is placenta soap is good?
Placenta Soap is known for its anti-wrinkle and whitening effect. A plant based soap, prevents further wrinkle formation and lightens pigmentation and dark spots.
Which fetal membrane take part in the formation of placenta in man?
In humans, the placenta is primarily formed from the chorion, which is one of the fetal membranes. The chorion develops from trophoblastic cells and interacts with the maternal endometrium to facilitate nutrient and gas exchange. Additionally, the allantois contributes to the formation of the umbilical cord, linking the fetus to the placenta. Together, these membranes support fetal development throughout pregnancy.
Does a blastocyst become placenta?
Yes, the blastocyst plays a crucial role in the formation of the placenta. After implantation into the uterine wall, the outer layer of the blastocyst, called the trophoblast, differentiates and contributes to the development of the placenta. The inner cell mass of the blastocyst eventually forms the embryo itself, while the trophoblast supports the embryo's nutritional and gas exchange needs through the placenta.
What is the medical term meaning abnormal implantation of the placenta?
Placenta previa, placenta accreta, placenta increta, and placenta increta are all conditions stemming from abnormal implantation of the placenta.
Where does implantation and formation of the placenta normally occur?
Implantation typically occurs in the wall of the uterus, where the embryo attaches and begins to grow. The placenta then forms from the outer layer of cells of the embryo and the uterine lining, facilitating the exchange of nutrients and waste between the mother and the developing baby.
Do cats have a placenta?
Placenta comes out after each kitten.
What becomes the chorion and forms the placenta?
The chorion is developed from the trophoblast layer of the blastocyst, which is the early structure formed after fertilization. As pregnancy progresses, the chorion contributes to the formation of the placenta, specifically by interacting with the maternal decidua to establish nutrient exchange and support fetal development. The placenta acts as a critical interface for maternal-fetal exchange, providing oxygen and nutrients while removing waste.
