Why do you say that 27 days is a new self? Will the cell be updated?

This is because human epidermal cells will grow new in about 27 days, so they become new themselves in 27 days. Just like snakes and other molting animals, the epidermis changes regularly every day. In other words, every 27 days, our epidermis will be renewed, which is different from before, and this is also the result of the constant renewal of epidermal cells. Our epidermal cells actually grow from the basal layer, then slowly keratinize until keratinization is completed, and finally they will fall off and be replaced by new epidermis. And all this, in fact, is invisible to us, and it is silently carried out in the micro-world.

It can be seen from the renewal of epidermal cells that cells will be renewed. Every new cell is split from the old one, and some cells will be lost in the process. Cells are the most basic unit of life, and the renewal speed of cells with different functions is different. For example, epidermal cells may be the fastest updating, while nerve cells in the brain are the slowest. In fact, biologists are still uncertain about the speed of cell renewal, but everyone agrees that it takes about seven years for all cells in the human body to renew, including the slowest cells.

As long as our human body is alive, the cells in our body will be constantly updated. This can also be called human metabolism. Cell renewal is fast and metabolism is fast, which is beneficial to our health. After metabolism, new healthier and more energetic cells will be produced and continue to work for the human body. With the growth of age, some cells in our body will lose the ability to renew, resulting in no new cells to continue to work for our body, which will lead to diseases. For example, after some cells in the brain are no longer updated, some functions are lost, and this is how Alzheimer's disease comes about.