1.Why is the fetus not so easily deformed? From the early pregnancy “all or nothing” phenomenon!
There is a phenomenon in early pregnancy called “all or nothing” phenomenon. This means that either there is or there isn’t, there is no such thing as half there and half not.
Within 14 days of the formation of the fertilized egg, regardless of the harmful factors to which the embryo was exposed (including drugs, toxins, radiation, etc.), there are only two possible outcomes: the embryo dies and miscarries, or the embryo is normal and unexposed to harmful factors with no difference! This is the so-called “all or nothing” phenomenon in the early stages of embryonic life.
Why does this phenomenon occur? The metaphor of building a space base was used earlier to describe such an arduous process. Because outer space is an extremely harsh environment for human beings, without sufficient protection, human beings cannot survive, not even in a disabled way. Human beings in the environment of outer space, there are only two possibilities: 1, build a reasonably survivable space base and live normally; 2, die soon.
There are too many natural harsh factors, relative to the tiny fertilized egg, to develop into an adult, the natural environment was originally quite complex and dangerous, including physical and chemical factors from outside the body, but also from the body’s immune factors and so on. Earth has gone through billions of years of evolution, from the simplest lifeforms to the evolution of human such a review lifeforms, this process has experienced numerous evolutionary failures. The success of each subtle change was born with the failure of thousands of subtle changes. So little by little, fine-tuning, precipitating the successes into the DNA sequence, complex life forms slowly formed, and finally humans emerged.
In the early stages of construction, the embryo first erects a defense barrier against the stimulation of external risk factors. The embryo at this stage is extremely sensitive, and no matter how good its genes are, the slightest accident will be lost and end in extinction. When the frontal fortifications are not sound enough, it is futile to establish the various systems in the rear, because the dangers are never far away and are always infringing on the embryo’s development. The embryo is so fragile that only those embryos that by chance construct a defense mechanism equipped with continuous protection against harmful factors have a chance to survive. Once they survive, the likelihood of malformation or death is very small.
2. The “error correction” potential of early embryonic cells!
Embryonic development is the process of dividing one cell into multiple cells, and then multiple cells continuously differentiate into different functional areas, which reorganize with each other to form systems, organs and tissues.
Due to the extremely harsh external and internal environment in the early stage of embryonic development, errors are extremely likely to occur in the process of functional differentiation. If some mechanism for self-correction of errors is missing during embryonic development, it is easy to think that the chances of the embryo’s eventual developmental success will be exponentially reduced.
Why is life on Earth so uninterrupted and continuous? It is clear that organisms have evolved this compensatory mechanism over the long evolutionary journey. Embryonic cells are primitive cells with multi-directional differentiation potential, and the earlier the embryo, the stronger the differentiation potential. (The familiar “stem cell” is a primitive cell with the potential to differentiate into several different cells, but the early embryonic cells are more primitive than these so-called “stem cells” because the very early embryonic cells, one cell has the opportunity to (This is how monozygotic twins are born.)
Cells in adjacent functional areas may have similar differentiation potential, and when a cell in a functional area is damaged, the remaining cells in it can proliferate rapidly, or some neighboring cells can proliferate and fill in to compensate for the loss of that functional area. But if the loss is too great, a defect may also form.
An artillery company is crippled, as long as the core members do not die, after recruiting and retraining, it reverts back to a highly capable artillery company. However, if the artillery company is beaten to the point of being left in the dust, or if it has just been crippled, and the new recruits have not had time to train, and then encounters a strong enemy, then the artillery company may be completely dead. This unit may become a unit without artillery.
3, evolution = trial and error, reproduction and fertility is also trial and error!
The evolution of living creatures, without the participation of intelligent design, relies entirely on a long evolutionary process, trial and error, and finally survived the species, in their DNA data, written on the experience of the failure of successive generations of species. The developmental process of the embryo is a recreation of a long evolutionary trial and error.
Trial and error never stops. It is difficult to imagine how many generations of intelligent life have emerged on Earth before modern humans, and they have all been destroyed into history, either because of their own genetic defects or because of the defects of social forms. In the process of trial and error, modern humans have survived and continued to reproduce, but whether this reproduction is sustainable in the long run remains to be tested by time.
The extinction of ancient Homo sapiens, the extinction of Easter Island civilization, and the extinction of Mayan civilization remind us that we are also in the process of trial and error.
Human embryos have a natural loss rate of up to 70%, which is mainly manifested by biochemical pregnancy, spontaneous abortion, fetal abortion, and empty gestational sac. Such a harsh elimination process is itself a recreation of the evolutionary process of life, which no one can escape from.
4. Most of the defects of embryos are early deaths – the “all or nothing” phenomenon of prolonged birth!
In other words, as long as the embryo is found to be alive and continues to develop in utero until mid- or even late gestation, the likelihood of the embryo being defective is very small.
5. It is a result of evolution to allow defective embryos to die naturally at a very early stage!
The human embryo has to develop in utero until 266 days of delivery. And there are mammals that, at the time of delivery, have only just completed organ differentiation and have only basic motor skills – like kangaroos. Kangaroos give birth at a gestational age equivalent to two months of human gestation, no vision, no lung function, can not breathe, relying on the skin capillaries to exchange oxygen directly with the air and crawl inside the nursery bag themselves to continue to develop. Such a fetus, to be in the case of immature organs, themselves had been subjected to a variety of harsh external stimuli. Can not tolerate the consequences of stimulation, is death, but also not deformity. In contrast, human beings are much more fortunate. After completing the basic differentiation of organs, the human embryo still develops under the protection of the mother’s womb until the heart, liver, lungs, kidneys, brain, digestive system and other various organs are more mature.
Therefore, if an embryo is still alive inside the uterus even in the middle of pregnancy and no structural deformities are found, its likelihood of malformation or death is actually very small.
In the second and third trimester, which is a critical period for organ differentiation, the embryo is at a high rate of functional differentiation and is very likely to develop malformations if it suffers a serious injury. And this window is actually very short, and life has evolved in such a way that it chooses to focus only on cell quantity and not on cell quality in the early stages of embryonic differentiation, in order not to create opportunities for harmful factors. At 2 months of gestation, the human embryo basically appears humanoid and small hands and feet can be seen, but the whole embryo is only a few millimeters, but the sparrow is small and full of organs. In fact, the time required for the differentiation of each small functional area is very short, so that the purpose is to give the enemy as little opportunity as possible to be left. When the rice has been cooked, the enemy can not do anything about it.
Despite this, congenital malformations are still inevitable, and not everyone can be so lucky. Fortunately, the final surviving deformities, many are not as serious as imagined. For example, congenital heart disease, is the most common type of malformation, most minor foramen ovale, atrial septal defect, ductus arteriosus, etc., after birth, there are still some can grow well on their own.
6.If “fetal” humans are so prone to malformations, how should “oviparous” fish and chickens live?
The biggest advantage of animals evolving from oviparous to fetal is that the fetus can be fully protected by the mother from being exposed to the natural world and directly affected by the harsh environment of nature.
How harsh the natural environment is, I think the people who cultivate the goldfish may be very vocal. Goldfish look so fancy and beautiful, many people do not know that the rate of mutation of goldfish is greater than we can imagine. Because the fish are reproduced in the water hatching, its DNA variation, fertilized eggs development and differentiation is extremely vulnerable to the temperature of the water, pH, pathogenic microorganisms and so on. Therefore, goldfish breeding masters, high on the breeding control and selection. It is difficult to breed excellent varieties, if the environment is not well mastered, the next generation is easy to mutate.
We are a bit unfamiliar with goldfish, let’s talk about chickens. When I was a child, we raised chickens at home, and every family in the village raised chickens, and I have seen many chicks hatching process, I have seen rotten eggs hatching, I have seen dead chicks in the eggshell, but I have never seen a deformed chicken hatching out of the lack of wings and legs. Harsh environment, the impact on the young embryo, more lethal, but also disabling, but compared to the lethal, or dead more, deformed less.
7. Double barrier during fetal development.
As a fetal human embryo, its development process is not known how many times safer than that of oviparous fish and birds. Any environmentally harmful substances, in order to harm the fetus, must first pass through the maternal body, the mother’s strong immune and metabolic function, can filter, inactivate and detoxify the vast majority of harmful substances. Even if there is some residual, it has to pass through a second powerful barrier – the placental barrier – before it can affect the fetus. The placental barrier, which usually only allows nutrients of very small size to pass through, and the vast majority of viruses, bacteria and toxic substances, will be difficult to pass through because of their size and other reasons. (Those who do not know pregnancy, drank twice, smoked a few days, or husband smoking at home, and sniffed a few of what drugs …… later do not take the matter! (I have to ask me, I can not answer “never deformed” “absolutely no effect” such words, to quote the words of a popular reality TV show recently “this is life”!)
8, the embryo is good, the fetus is healthy or not, time will tell!
”The first thing you need to do is to take a look at my ultrasound and see if my child is healthy.
There are often pregnant mothers who come to me with an ultrasound sheet from early pregnancy. How can I answer this question? Do I say it is healthy? Or should I say no? I really don’t know!
Whether the embryo is good or not, and whether the fetus is healthy or not, we have to rely on time to verify, no one can say, not even the blood test, not even the ultrasound. The most we know is that the fetus is still alive, and if it’s still alive, it’s awesome. The embryos that are still alive today are definitely more powerful than the ones from yesterday, and the ones that live until tomorrow will be even more powerful.
9, “took a chest X-ray, can the child want?” “Ate xxx medicine, can the child want?” “took the plane, the child can not want?” …
I will answer: “All can want!”
10. “Will the child be deformed?”
I would answer: “Every embryo can be deformed, no matter what factors it has been exposed to, or not, but the embryo that survives is the bull. In order for a fetus to come into the world, it must be able to accept the many trials and tribulations of a harsh environment. I don’t know whose fetus can withstand it and whose can’t, but only a relatively healthy fetus has a chance of surviving, and this is a prerequisite. And in contrast, a deformed embryo that survives is even more awesome. So, what we have seen, born and still alive deformed embryos are extremely rare.”
11. “How can I know if there’s something wrong with the baby?”
I replied, “We can only take one step and wait and see. Because there is no means to see all the defects before the child is born. But a fetus with no defects found until birth is, by and large, good. That’s the only way to think about it. All fetuses are equal in this matter, not because you’ve had X-rays, or used any medication, there is nothing special!”
12. “But there are still so many children born with deformities, how can this be explained?”
A: There are always some children born with defects, or deformities, or mental retardation, and some autism, which is not visible until they are several years old. These are unavoidable. Just like when we go out in the car, there are always people who get into car accidents, and every year, countless people are killed and disabled because of car accidents (and those who are bitten by poisonous snakes, eat fish stuck in the thorns, walk by bricks, and many more). So do we need to be scared to death as soon as we get in the car? The statistics of birth defects is a matter of concern for the national public health administrators, we ordinary people should still do what we do. Who may be deformed, who will not be deformed, who will not know, there is no need to worry so much!
Do your best, and God willing! But do good, do not ask the future! Repeat what I said before: about reproduction and reproduction of this thing, humans are not much more privileged than animals, we can only quietly wait for the heavens to give us a predetermined result slowly revealed. All prenatal tests, prenatal diagnosis, are not designed to change the outcome, but only to let the answer be revealed in advance.
In 2010, there were more than 3.9 million traffic accidents in China, resulting in more than 250,000 injuries (not including In 2010, there were more than 3.9 million traffic accidents in China, resulting in more than 250,000 injuries (excluding bruises, sprains, and concussions that are unrelated to pain and can be observed in the emergency room for a few hours before going home) and more than 60,000 deaths.