Information on the importance and functions of the placenta.
The placenta is the organ that carries out nutrition, respiration and excretion for the embryo, and it is fully formed during the fourth month.
Biologically the placenta is an organ developed by mother and child in symbiosis and consisting of fetal and maternal parts. The fetal part is formed by the chorion frondosum, the maternal part is formed by the stratum compactum and the intervillous spaces of the decidua basalis.
Placenta via Wikipedia
By the fourth month of pregnancy, the placenta is a well-developed organ. As the pregnancy continues, the placenta increases in area and thickness. The increase in the placenta area accompanies the steadily expanding uterus. In fact, the placental attachment occupies one-third of the internal surface of the throughout the remainder of the pregnancy, the increase in placental thickness is a result of the elongation of the villi.
Fetus via Wikipedia
The functions of the placenta fall into several groups. (1) Endocrine: Hormones including gonadotropin, estrogen, and progesterone are produced in large amounts. (2) Excretion: Products of fetal metabolism can cross the placenta into the maternal circulation, the placenta functioning like a kidney. (3) Respiration: Oxygen supplied by the mother diffuses across the placental membrane into the fetal blood. The placenta thus serves as an efficient lung for the fetus. (4) Nutrition: Proteins, carbohydrates, water, fats, inorganic salts, and vitamins can all pass in different forms from the maternal to the fetal blood. (5) Protection: Foreign particulate matter such as bacteria is unable to cross the barrier unless the placenta itself becomes actively involved in the inflammatory process.
The placenta has a flattened circular shape, with a diameter of about 8 inches, a thickness of about 1 inch, the fetus is suspended from the placenta by the umbilical cord.
At birth, a few minutes after the delivery of the child, the placenta separates from the uterine wall and is expelled from the uterine cavity as the result of the contractions of the uterine musculature. The line of separation occurs through the spongy layer of the decidua basalis.
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