In fact, conjoined twins is identical twins, developed from a fertilized egg. In the early embryo, because the cells have not yet differentiated, the embryo is divided into two embryos with the same cell content, which develop independently. In conjoined human, the early embryo is partially divided, and the parts are still connected together, while the cells in each layer of the embryo have special functions, and the genes are selectively expressed to produce various tissues and organs of the human body.
Because it is not completely separated, the separated part develops independently, and the undivided part develops into two organs and tissues, so the conjoined person has the same sex, one is a woman and the other is definitely a woman. The probability of overall occurrence is very low, and the probability of identical twins is already very low. On the basis of identical eggs, the total probability is only one in 200,000.
There are many conjoined cases, the most common one is the connection between the chest and back, some are the connection between the buttocks and the brain, some are the connection between the abdomen, and sometimes the heart and brain are used together. In fact, it is only one person, and such an experience will seriously affect people's ability to survive and adapt. Some died in the fetal period due to insufficient breathing, lung infection or other problems, and some can grow up.
At present, there are some individuals who are seriously conjoined but survive in the world. There is a pair of conjoined sisters in America, with only two heads, and other organs and tissues are used by * * * *. At present, they are still alive and are good teachers. What is even more rare is that two heads and two independent consciousness can perfectly control the human body. In general, the two kinds of consciousness can't be unified. The two sisters can't walk, but they can ride bicycles.
At present, some types of conjoined people can be separated by surgery, mainly because there are no important organs connected. However, when important organs such as the heart are used, only one baby can survive after separation. This requires parents to make choices. In the past, there were some cases of conjoined separation in China, but some parents would choose not to separate, so as to ensure the survival of two children, even though they may only have one body.
So American sisters have always been conjoined. Excluding these problems, conjoined people, like normal people, have normal physiological activities and naturally eat fat. But it is still very different from normal people, mainly because of metabolic problems. There are many photos of adult conjoined bodies on the Internet, all of which are relatively thin, which is caused by high basal metabolism.
Like American sisters, * * * has two heads when using the body, but the brain has a high demand for energy and oxygen. When using the body, * * * eats the amount of one person, but supplies two brains, so the basal metabolism will be higher, and the result of high consumption is that it is not easy to gain weight; Some people will get fat, for example, the chest and abdomen are connected together, so the conjoined person will move slowly and the energy demand for exercise will be reduced. Lack of exercise is an important cause of obesity. Similarly, in the United States, there are a pair of conjoined brothers. Their conjoined way is quite special, just like a normal person's abdomen grows another body. This body structure is too tired to walk, so they eat more fat.
Siamese people often have other deformities. The skull structure of conjoined sisters in the United States is a little deformed and doesn't look as round as ordinary people. There are some extreme types that only connect the upper body and buttocks without legs, which will of course affect diet and energy metabolism; Most conjoined people whose heads are separated from other parts still have obstacles in body control. The heart can only walk in one place, but one brain thinks east and one brain thinks west, which also affects energy consumption.