Release date: 2014-05-06
The normal metabolism of cells does not make you a different person. "Seven years of itching" is related to changes in the synaptic connections of nerve cells in the brain, because the number of synaptic connections and the strength of the connections determine our sensory thinking memory. "Seven years of itching" is also related to the secretion and genes of dopamine.
Now "Seven Years of Itching" has become a special description of emotional changes, and has become a golden sentence for many people who have lost love. They explain the theory of seven-year itch: the metabolism of human cells is replaced every three months, and new cells are born as old cells die. Due to the different metabolic time and interval of different cells, it takes seven years to replace all the cells. In other words, physiologically, we are another person every seven years.
Does the cell really have "seven years of itching"? Is our emotional change related to cell metabolism?
There are a total of 40 trillion to 60 trillion cells in the human body. We need to provide energy through the metabolic activities of the cells. In the process, there are continuous cell deaths and new cells appear. In terms of cell structure and function, new cells are the same as decaying cells, so they do not have a big impact on the human body. Therefore, the normal metabolism of cells will not make you a different person.
There is indeed a cycle of cellular metabolism, but not all cells are updated in the same cycle. For example, the renewal period of skin epithelial cells is 28 days, the taste cells on the taste buds are updated once every 10 days to 2 weeks, the renewal of gastric mucosal epithelial cells is 6 days, the renewal period of intestinal mucosal cells is only 3 days... and some replacement cycles Very long cells, such as cardiomyocytes, Swedish scientists in 2009 have shown that cardiomyocytes are updated at a rate of 1% per year. Some brain cells are never renewed, such as central nervous cells, which have been set since the day of birth, cannot be increased or updated, and the central nervous cells will decrease after age. The constantness of the central nervous cells is also the reason why our memory can last forever.
This is only the metabolic cycle of some cells, and most of them are estimates, not so precise. Because there are too many types of cells in the human body, the number of cells in each species is also large, and the situation is complicated. For example, the lifespan of cells in different positions of the same organ is different, and the health status of each person is different, and the cell renewal speed is also different.
Therefore, the statement that "cells are replaced every three months" is also incorrect. The theory that systemic cells change for seven years is not supported by evidence.
It is not the metabolism of cells, but the synaptic connections of nerve cells in the brain. The number of connections and the strength of connections determine our sensory thinking. Memory also determines our ability to receive and preserve new information. There are 10 11th-order nerve cells in the brain that communicate with each other to form 100 trillion synapses. The interaction of nerve cells forms a cluster of nerve cells that form different regions of the brain that control human behavior. Although nerve cells are unable or difficult to regenerate, the ability to connect between synapses can be altered. If you think that you have a change in thinking and memory compared to a few years ago, it is related to your daily brain habits.
"Seven years of itching" is also associated with the secretion of dopamine. Dopamine is a key neurotransmitter in the hypothalamus and pituitary gland that directly affects human emotions. Love can promote the secretion of dopamine, which makes people feel happy and thinks that it is the happiness that the other party brings. But it can't be maintained all the time. When the brain feels tired, the dopamine secretion is reduced or disappeared, people will wake up from the dream of love, and then negate the feelings and find new "stimulus."
"Seven years of itching" is related to genes. Collaborative research by the University of California at Berkeley and Northwestern University shows that genes affect individual marital satisfaction by affecting individual sensitivity to emotional atmosphere.
Source: People's Network
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