Human Hair
Why does human hair grow long, while the skin of animals falls short?
Well, a fairly random question, but why human hair continue to grow to great lengths, whereas, for example, dog fur grows only to a specific length and then stops. Are there other animal hair is growing besides humans?
Mammals have hair on most of their bodies, but at some point during evolution, humans lost the skin covering …. Researchers at Washington University School of Medicine in St. Louis say the hair on the head is somewhat different from fur, it stops growing when it reaches a certain length, but our head hair continues to grow …. One reason could be that under the microscope a hair follicle taken leg would be about the same as one of the head. Our human "fur" if you will – the hair under the arms, legs and elsewhere – is anatomically Both identical to head hair … scalp hair and skin of the body grow in cycles. The hair follicle produces a strand of hair during its active growth phase, called anagen. Then the growth slows, and the follicle-concept "for a while, the telogen phase. Then there is exogenous when the hair falls out and the follicle begins to grow a new strand of hair in the anagen phase begins again. The hair on the leg usually grows from 19 to 26 weeks and then falls. The hair on the head continues to grow between two and six years. Neufeld and Conroy the hypothesis that, although the same hair follicle may be the same, the hair follicle growth cycle must be regulated differently in the head than in other parts of the body. There is a slight difference in the levels of keratin in human hair. Keratins are fibrous proteins that form the basis chemistry of hair, fingernails, rhinoceros horns and other external features of many animals. The keratin content of human head hair is different from what found in the skin in chimpanzees and gorillas, our closest biological relatives. One possible reason for this difference is a segment of human DNA called pseudogene. The actual gene, known as ΦhHaA produces a keratin protein in chimpanzees and gorillas. Although the same DNA sequence is conserved in humans, the cells do not use it to make protein. That's why scientists call a pseudogene. Neufeld and Conroy have ideas about how to identify differences between head hair and fur. They say studies will be difficult because there can be an experimental model. But they believe it might be possible, for example, to have a hair follicle human head and another in the leg and carried out gene chip experiments to learn about the differences in the genes that regulate the activity of the follicles. A similar study of the human head hair and skin chimp could also provide clues. But even if it is possible to identify the factors that make hair grow head differently than body hair, scientists may never know why humans evolved head hair that is so different from our animal cousins closer. We may never know the answer …….
How to Curl Human Hair Extensions
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