![](\"\/wp-content\/uploads\/2024\/02\/thum_umbilical_cord_2_en.jpg\")
\n <\/picture>\n<\/figure>\nThe placenta is a protective organ that helps the fetus survive and grow in the mother\u2019s body by connecting the fetus to the wall of uterus. The fertilized egg becomes a saclike embryo after four or five days of fertilization. Then the inner part of the embryo grows to become a fetus, and the outer part of it becomes the umbilical cord and the placenta. After the fertilized egg implants in the uterus, the outer cells of the embryo change into what looks like bumps, burrow into the uterus lining by producing proteases, and find blood vessels and form tissue. Just as the roots grow deeper as the tree grows, the placenta also makes more blood vessels inside the womb as the baby grows.<\/p>\n
The connection between the embryo and the uterus is weak in the beginning of pregnancy. However, as the placenta is completed, the fetus gets attached to the mom securely just like an anchored boat. The reason why the miscarriage rate drops dramatically after week 12 of pregnancy is because that is when the placenta is formed completely. Kangaroos and koalas give birth to their young prematurely because of the weak development of their placentas, and they raise their young in their pouches until they grow to a certain point.<\/p>\n The umbilical cord which starts from the belly of the fetus gets connected to the placenta, connecting the mom and the baby directly to serve as a medium in exchanging materials between them. The mom\u2019s oxygen and nutrients are provided to the fetus, and the fetal waste such as CO\u2082 is transported to the mom. What is interesting is antibodies. During the first six months after birth, babies don\u2019t easily get infectious diseases such as measles or the smallpox, because they are born with antibodies from their mothers. However, since not all maternal antibodies can pass through the placenta, they have no immune system to some diseases such as the whooping cough or the chickenpox.<\/p>\n Also, the placenta selectively lets other materials as well as antibodies pass through. In other words, it plays the role of a filter, letting beneficial materials pass through to reach the fetus and blocking harmful materials. Thanks to the placenta, the fetus has no problem surviving in the mom\u2019s body even if they have different blood types. It is because the placenta filters red blood cells and antibodiesa1<\/sup>. Thanks to the placenta, although the mom catches bacterial infections, the baby doesn\u2019t get infected.<\/p>\n However, some drugs or tiny viruses can reach the fetus with serious impact on it. For example, small, fat-soluble molecules such as nicotine and alcohol can pass through the placenta and reach the fetus, which is why it requires extreme caution.<\/p>\n From the seventh month of pregnancy, the fetus can detect lights and shadows. When the mom feels the light, the melatonin secretion is reduced, and such change is conveyed to the fetus through the placenta. It means that the fetus can feel the light which the mom is looking at, without looking directly at the light outside the mom\u2019s body.<\/p>\n The placenta not only plays the role of a medium but also produces nutrients and hormones that are necessary for the mother and the fetus. The nutrient from the mother is stored in the form of glycogen in the fetus, and an adequate amount is provided to the fetus each time. Therefore, even when the mom\u2019s supply of nutrient is not consistent, the fetus can stably get nutrients. The placenta also provides the fetus with the combination of cholesterol and fatty acid as well as glycogen.<\/p>\n Also, it secretes human chorionic gonadotropin [hCG], which maintains pregnancy, in the first trimester of pregnancy. As it enters the second trimester of pregnancy, it secretes a large amount of progesterones and estrogens which develop the uterus, helps with smooth blood circulation, and keeps the uterus from contracting, and this way, it helps the fetus grow safely. The hormones that decide the time of delivery are also secreted from the placenta.<\/p>\n It has been a mystery for a long time how the placenta can exist in the mom\u2019s body without decomposing. The immune system normally attacks the substances with different genes in order to protect the body. That\u2019s why it is hard to understand how the placenta which is half from the mom and half from the fetus can exist.<\/p>\n Professor Phil Lowry at the University of Reading explained that it is possible because the placenta acts like a parasite to avoid attack by a mother\u2019s immune system. As for parasites, the molecules called phosphocholines, which are present on the surface of their cells, trick a person\u2019s immune system into recognizing them as its own cell. In the same way, most proteins synthesized in the placenta have phosphocholines, using the strategy to deceive the system of the mother\u2019s body. The placenta, which is an organ solely for the fetus, comes out of the mom\u2019s body with a light pain once the baby is born and its function is done after delivery.<\/p>\n The fetus that cannot do anything on its own grows inside the mom\u2019s womb, and is born as a confident living being. This is possible thanks to the umbilical cord and the placenta which connect the mom and the baby. The mother\u2019s body gives a secure nest to the fetus and with no condition everything necessary for the fetus to sustain its life, and takes in everything that becomes unnecessary.<\/p>\n All people born in this world have the mark of the umbilical cord that shows they were one with their moms. It is the belly button. From the moment a life begins to exist, the mom and the baby are connected together, forming an inseparable relationship.<\/p>\n![](\"\/wp-content\/uploads\/2023\/02\/thum_umbilical_cord_3.jpg\")
\n <\/picture>![](\"\/wp-content\/uploads\/2023\/02\/thum_umbilical_cord_4.jpg\")
\n <\/picture>\n<\/figure>\n\n