Why is hair growth different in different parts of the body?

Except for the palms, soles and lips of the human body, the rest of the skin is mostly hairy. Looking at similar hairs, many people will wonder why their lengths are different? The nutrients in the same human body should be basically the same everywhere, but the hair and beard of a man can always grow, and the eyebrows and hair on the skin do not have to worry about growing even if they are not taken care of. What’s the reason for this? Let us explore the truth together.

Why is the hair growth of the same person different? To answer this question, let’s take a look at how the hair grows first. The structure of the hair is divided into two parts: the hair shaft and the hair root. The hair shaft is the visible part of the exposed skin. It is generally composed of keratinized dead cells. Therefore, it will not cause pain if we go to haircut or shave. Hair roots grow in the skin and are wrapped by hair follicles. The swelling of hair roots and the ends of hair follicles are called hair bulbs. Hair bulbs are active in cell division, and hair bulbs are also hair growth points. The newly grown hair will connect with the original hair and push the original hair out, which forms the growth of hair. Hair can continue to grow even if it is cut, but if the hair follicle becomes inflamed or infected, no new hair will grow.

Hair is formed by the division of hair mother cells in the hair follicles, but why does the length of the hair, sweat and eyebrows vary? This is because the position of human hair is different, and the growth rate and growth life of the hair are also different. But all hair has three growth stages, namely the active growth period, the degeneration period and the resting period.

For hair, under normal circumstances, hair grows the fastest and has the longest life span. Hair grows about 0.3 to 0.5 mm every day. It is more intuitive for hair dyers, and within a few days you can see that the gray hair that was previously dyed is growing again. The life span of hair is generally 3 to 6 years. Even if it is not cut, the hair will fall naturally, so every time we wash our hair, the hair will fall out. This is the natural death of the hair.

Basically, 50 to 80 hairs die every day. Of course, if a person’s body is better and the hair follicles are more nutritious, the hair can be overlong. We don’t have to worry too much about the hair that falls every day. When there is death, there will be new life. The number of new hair and the number of fallen hair can basically be the same. When the number of new hair can not keep up with the number of fallen hair, the hair has entered the degeneration period. In all hairs, the growth rate of beard and hair is more consistent. But the life span of a beard is basically 1 to 3 years, so it is impossible for you to have a beard as long as your hair.

In contrast, the growth rate of human eyebrows, eyelashes, and sweat hair is much slower, basically only 0.1 to 0.18 millimeters per day. The life span of eyebrows, eyelashes and perspiration is also relatively short, usually four months, so many women will do it again every few months when grafting eyelashes.

The growth rate of armpit hair and pubic hair is between the speed of hair and eyebrows, and the life span is also between the two, about one and a half years, so their displayed length is also between the two.

Human beings have gone through hundreds of thousands of years of evolution. The different hair lengths throughout the body are also to adapt to or cope with nature. For example, people in desert areas have strong sweating hair, and long eyelashes are good for wind and sand. They are the result of human evolution.

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