In the course sharing of the previous issue, we learned that from the moment human beings were born, our immune system has been helping us resist viruses and other pathogenic sources in order to protect our own life and health.
Through modern science, we all know that life is composed of hundreds of millions of tiny cells, and each human body is composed of about 40 trillion to 60 trillion cells, which make up our various tissues and organs. , And complete different missions.
However, in the long river of life, the cells existing in our bodies are no longer the original batch of life. For a person, the beginning of life comes from the encounter of a sperm and an egg, and from a fertilized egg to a mature newborn, the fertilized egg undergoes countless divisions, and each division produces new cells.
Because cells also have a life cycle, cells need to undergo constant metabolism to maintain the continuation of life.
As the main genetic material, DNA guides cell metabolism. Since the Swiss biochemist Friedrich Michel isolated DNA from the pus in surgical bandages in 1869, mankind has written a magnificent chapter in the history of life sciences.
It can be said that DNA is the artist of life, and every life, whether it is an animal or a plant, cannot be separated from the manipulation of DNA. For individual life, such as a person, if you want to grow to mature and live forever, you need to divide, proliferate and grow the body's cells under the strict guidance of DNA, that is, constantly copy new cells to satisfy the body. The survival needs of different organs and different tissues.
However, we also know that the human body is composed of tens of trillions of cells. It is such a huge workload to complete a complete renewal of human cells, not to mention that the renewal of cells in our body's organs never occurs more than once in a lifetime.
Although DNA is the greatest life artist we know, no matter how great and powerful a life artist is, when faced with millions of billions of operations, he will inevitably get confused. This is like a computer with no matter how sophisticated. There may also be mistakes in calculations.
The direct consequence of DNA manipulation errors is the production of erroneous cells in our body, which are inferior cells in our body. Modern medicine has proved that the occurrence of defective cells in the process of cell replication occurs every day, which means that each of us will have a certain amount of defective cells in the body every day.
Perhaps you think that the number of these defective cells is small relative to the number of healthy cells in the human body, and even if they exist in our body, they are of little importance.
But I'm sorry, these defective cells are not as simple as you think. If left alone, the consequences will be disastrous. Their replication speed is tens or even a hundred times faster than normal cells, and then they will greedily and unscrupulously absorb our nourishment and continue to grow themselves. Over time, they will become more powerful and directly harmful. In our lives, the tumors we know are formed.
If there are extremely bad types among them, they will evolve into malignant tumors after a long period of development.
Malignant tumors that have formed, our human body naturally does not arrange its position. In order to allow itself to grow up, it will cultivate its own blood vessels, madly absorb the nutrition of our normal body tissues, and oppress the normal organs around us, which will cause us over time. The normal organs of the human body cannot work normally. For example, stomach cancer, this kind of cancer cells frantically absorb the nutrients that the stomach should absorb, making our stomach weaker and weaker, making it difficult for our stomach to perform its normal functions. Once our stomach is down, the whole person will have all kinds of problems, such as being unable to eat, unbearable pain, losing weight, various complications, and if not treated, we will lose our lives.
Seeing this, do you dare to look down on these defective cells?
Having said that, it is naturally impossible for our human body to just let it go and let these tiny defective cells develop lawlessly. Earlier we learned about the three major responsibilities of the immune system, one of which is immune surveillance. To put it bluntly, it is to keep your eyes open and keep your eyes on these defective cells to prevent them from destroying them. Once discovered, they will send out NK cells and macrophages. , T cells, dendritic cells, etc., attack these defective products for the first time, prevent it from replicating, prevent it from expanding, and prevent it from becoming cancerous, until they are completely killed.
However, when some people’s immune system activity is low, they may not be able to clean up these inferior cells in time, because these inferior cells are evolved from normal cells in our body, which are extremely camouflaged and easily escape the recognition of the immune system. And kill. Once the immune cells appear to be "invisible", "uncontrollable" and "unkillable" defective cells, our body may have the possibility of cancerous growth.
To use a very simple analogy, we all know that smoking is bad for health. According to epidemiological statistics, the incidence of lung cancer among long-term smokers is 20-40 times that of non-smokers. Because smoking continues to create obstacles to the lung organs, it also brings tremendous pressure to the immune cells working in the lungs. As we said earlier, at this time, the immune system is prone to "being too late or unable to deal with it." "In the case of a small number of cancer cells, the probability of developing cancer will naturally increase if you stay in this situation for a long time.
Therefore, the occurrence of tumors has a deep-rooted relationship with the level of our own immune activity.
I also want to remind everyone here that we must always pay attention to our immune activity level. In our daily life, we should add more food or nutrition to maintain the immune level, maintain good living habits, and do not let these defective cells and Cancer cells have opportunities.
In the next course, I will share with you the role of immunity in cancer treatment.
References：
https://baike.baidu.com/item/%E4%BA%BA%E4%BD%93%E7%BB%86%E8%83%9E/7113429?fr=aladdin
《免疫学原理》周光炎主编 科学出版社 P345-350
