The surface of the skin is the stratum corneum composed of fully keratinized keratinocytes. Keratinocytes are basal cells that are constantly differentiated, undergoing acanthosis, and the granule layer gradually migrates to the stratum corneum. The flat shape has no nucleus and continues to disintegrate and form a so-called “dander”. The time of this evolution process is called the epidermal growth cycle, which takes about 3 to 4 weeks, also known as the skin renewal rate.
lipid membrane skin surface sebum and the stratum corneum to its surface moisture emulsified form together constitute a protective barrier layer on the outermost surface of the skin, it plays a very important role.
On the one hand, it protects various tissues and organs inside the body from various damages in the external environment, such as mechanical damage such as friction, pulling, squeezing, impact, etc., physical damage such as electric shock, illumination, and magnetic sound. Chemical damage such as acid and alkali corrosion, especially the dense stratum corneum can prevent bacteria and viruses from entering the skin. In addition, the free fatty acids in the lipid membrane of the skin surface make the pH value of the skin surface acidic, and the growth of many bacteria Inhibition, so that the body is protected from microbes.
On the other hand, the semi-permeable membrane properties of the stratum corneum can prevent the loss of nutrients in the body. The amount of water lost by adults through the skin is about 240-480 ml per day, but if the stratum corneum is removed The loss of moisture will increase by more than 10 times.
It can be seen that when we take a bath, we scrub the skin with a bath towel, often causing premature exfoliation of keratinocytes that have not been completely keratinized, or even completely exfoliating the stratum corneum, exposing bright red granules or spinous skin, making the skin The barrier protection is greatly weakened, the body is easily damaged by the external environment, and it is easy to accelerate the aging of the skin in the long run, so it is not recommended to bathe with a bath towel.