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Anonymous users2024-02-15The principle of tanning, which is how melanin is formed.
When irradiated by heat or sunlight**, melanocytes located within the basal lamina are excited and activated, and they are present in a 10:1 ratio within the basal cells, which have a dendritic shape and shuttle through the epidermal cells. Melanocytes contain pigment granules, which synthesize melanosomes in the crude endoplasmic reticulum, which catalyzes a series of tyrosine reactions and generates melanin proteins, while tyrosinase will be inactive and act as a transporter to transfer them to keratinocytes.
The more melanin is transferred to keratinocytes, the darker the skin tone. After people of the same skin color are also exposed to the same amount of sunlight, why are some people tanned and some people's ** has not changed much? This has to do with a number of factors.
It mainly depends on how much melanin is produced and how much melanin is transferred to keratinocytes, that is, the more melanin is produced and the more it is transferred to keratinocytes, the darker the skin tone, and vice versa.
Fact 2: The principle of tanning.
I believe that many Asian women are very concerned about skin whitening. There are many whitening products on the market, but how many people really know or understand how melanin is formed? Why do some people tan easily and others don't?
Before you buy whitening products, let's talk about the principle of tanning and understand the truth of the facts.
How is melanin formed?
When irradiated by thermal radiation or sunlight**, it excites and activates the stratum located in the basal layer
basale), melanocytes (present in a 10:1 ratio within basal cells), which have the shape of tree branches and shuttle through epidermal cells.
Melanosomes are synthesized in the crude endoplasmic reticulum, and tyrosinase, which is located in the Golgi apparatus, will catalyze a series of reactions in the melanocyte and generate melanin protein, while tyrosinase will be inactive and act as a transport to transfer it to keratinocytes. Therefore, the more melanin is transferred to keratinocytes, the darker the skin tone.
People who are afraid of black do not like melanin, however, melanin has its benefits, it has the effect of protecting the body against ultraviolet rays.
When the body is exposed to ultraviolet light, the melanocyte activating enzyme (tyrosinase) accelerates the catalytic action to produce melanin.
For example, two people with different skin tones, after being exposed to the same amount of sunlight for the same time, those with lighter skin tones are prone to redness, for example, we often see foreigners sunbathing, getting red but not tanning. In addition, people with light skin tones are also prone to burns, while people with darker skin tones are less likely to burn.
It can be seen that melanin can block the damage of ultraviolet rays within a certain limit. That is, ** will be red or even black after being exposed to sunlight, which is caused by the accumulation of melanin in the superficial layer of the epidermis.
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Anonymous users2024-02-14Because the ultraviolet rays in the sunlight are harmful to the human body. If you are exposed to more sun, you will increase melanin to prevent and reduce the damage of ultraviolet rays to people, which is an instinctive response of biological self-protection.
Let's use a cucumber to compress this.
It may be related to one's own constitution, and it cannot be ruled out that there is a blood disease. People who are relatively weak in the body may have adverse symptoms such as fatigue and soreness in the waist and knees after basking in the sun, and people with insufficient cerebral blood supply may also have vasodilation and insufficient blood ** when exposed to the sun, which will be accompanied by weakness of limbs, dizziness and headache and other adverse conditions. Cerebral insufficiency is best preceded by oral blood volume replacement drugs** as directed by the doctor.
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Although the ultraviolet rays are not as strong as in summer, they also have ultraviolet rays, so sunscreen is to take a bath all year round to protect from the sun, and in winter, you can use sunscreen products with a slightly lower sun protection index.