placenta development

Definition

Target type: biologicalprocess

The process whose specific outcome is the progression of the placenta over time, from its formation to the mature structure. The placenta is an organ of metabolic interchange between fetus and mother, partly of embryonic origin and partly of maternal origin. [GOC:add, ISBN:068340007X]

Placenta development is a complex and fascinating process that begins with the implantation of a fertilized egg into the uterine wall. This process involves a coordinated interplay of maternal and fetal tissues, leading to the formation of a specialized organ that facilitates nutrient and gas exchange between the mother and the developing fetus.

**1. Implantation:** After fertilization, the fertilized egg, now called a blastocyst, travels down the fallopian tube and implants into the endometrium, the inner lining of the uterus. The blastocyst consists of an outer layer called the trophoblast, which will give rise to the placenta, and an inner cell mass, which will develop into the embryo.

**2. Trophoblast Invasion:** Once implanted, the trophoblast cells proliferate and invade the endometrium. These cells secrete enzymes that break down the uterine lining, creating space for the developing placenta. The trophoblast differentiates into two distinct layers: the syncytiotrophoblast and the cytotrophoblast.

**3. Syncytiotrophoblast Formation:** The syncytiotrophoblast is a multinucleated layer that forms from the fusion of cytotrophoblast cells. It invades the maternal blood vessels, establishing the maternal-fetal blood circulation. The syncytiotrophoblast is responsible for nutrient and gas exchange between the mother and the fetus.

**4. Cytotrophoblast Proliferation:** The cytotrophoblast continues to proliferate and forms finger-like projections called chorionic villi. These villi extend into the maternal blood spaces, increasing the surface area for exchange.

**5. Development of the Chorionic Plate:** The chorionic villi eventually form a network called the chorionic plate, which is the fetal component of the placenta. The chorionic plate contains fetal blood vessels that connect to the umbilical cord.

**6. Decidua Formation:** The maternal tissues surrounding the implanted blastocyst also undergo changes, transforming into the decidua. The decidua provides a supportive and nutritive environment for the developing placenta.

**7. Placental Growth and Maturation:** As the pregnancy progresses, the placenta continues to grow and mature. The chorionic villi become more complex, and the syncytiotrophoblast develops specialized structures for nutrient and gas exchange.

**8. Placental Functions:** The placenta plays a crucial role in supporting the fetus throughout pregnancy. Its primary functions include:
* Nutrient and gas exchange: The placenta facilitates the transfer of nutrients, oxygen, and waste products between the mother and the fetus.
* Hormone production: The placenta produces hormones such as hCG, estrogen, progesterone, and human placental lactogen, which are essential for maintaining pregnancy and preparing the mother's body for childbirth.
* Immune protection: The placenta acts as a barrier, protecting the fetus from the mother's immune system.

**9. Placental Delivery:** After birth, the placenta detaches from the uterine wall and is expelled from the mother's body.

Placenta development is a dynamic and tightly regulated process that is essential for the successful development of the fetus. Any disruption to this process can have serious consequences for both the mother and the baby.'
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Proteins (12)

Compounds (588)