Naked Science Forum
Life Sciences => Physiology & Medicine => Topic started by: neilep on 18/11/2007 21:32:02
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Dear All Hirsute Hairxperts ,
Hair is great !!...hair is my all time favourite natural fur covering shaggy type warmth skin covering thing !
But....does all the hair on my body grow at the same rate ?
Eyebrows, eyelashes, head hair, chest hair, legs, arms, hair in norty places ?
I realise that each area has a certain limit to length but is the rate of growth the same all over ?
Ta
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You're absolutely right! Hair is faaaaaaaaaabulous
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fwww.travelswithsheila.com%2Fmini-hair3.JPG&hash=54e5ad9bd1c881e2f83082e02b53892f)
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fwww.basetree.com%2Fthumbs%2FGlare_and_Purple_Hair.jpg&hash=56865f0627f5af7eb14bfcd120d648a5)
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fwww.venushairhouston.com%2Fanimallovers%2Fpoodle_before_after.jpg&hash=d427e8eb2812ad4523b39d3b907093e4)
As you guess, hair growth is not all the same and not all hair is just hair.
A very hairy affair really.
Blame the hormones! [;D]
The rising level of male hormones (androgens) during puberty causes a transformation process of vellus hair into terminal hair on several parts of the body. The hair follicles respond to androgens, primarily testosterone and its derivatives; the hair in these locations can be thus termed androgenic hair. The rate of hair growth and the weight of the hairs increase. However, different areas respond with different sensitivities. As testosterone levels increase, the sequence of appearance of androgenic hair reflects the gradations of androgen sensitivity. The pubic area is most sensitive, and heavier hair usually grows there first in response to androgens.
Areas on the human body that develop terminal hair growth due to rising androgens in both sexes, men and women, are the underarms and the pubic area. In contrast, normally only men grow androgenic hair in other areas.
Individual hairs alternate periods of growth and dormancy. During the growth portion of the cycle, hair follicles are long and bulbous, and the hair advances outward at about a third of a millimeter per day. After three to six months, body hair growth stops (the pubic and armpit areas having the longest growth period). The follicle shrinks and the root of the hair grows rigid. Following a period of dormancy, another growth cycle starts, and eventually a new hair pushes the old one out of the follicle from beneath. Head hair, by comparison, grows for a long duration and to a great length before being shed. The rate of growth is approximately 15 millimeters, or about ⅝ inch, per month.
and even more on http://en.wikipedia.org/wiki/Hair#Growth (http://en.wikipedia.org/wiki/Hair#Growth)
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Eyebrows, eyelashes, head hair, chest hair, legs, arms, hair in norty places ?
Tis also interesting that head-hair and body-hair is roughly circular in cross-section (cylindrical), while pubic hair is more rectangular in cross section. This may be related to the latters' wiry-ness...
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As I have stated before, pubic hair growth appears to be accelerated and it's texture changed, but most importantly no longer falls out when horizontal bedrest is avoided. People using Inclined bed therapy have noticed they no longer have the proverbial short and curlie’s, and like myself have to trim off their pubes or knit a scarf with them to keep warm. I believe this is because the circulation to the hair follicles is maintained by gravity and that sleeping flat compromises this circulation. I am sure it slowed down my balding head hair also and I conducted a sample collecting of my hair on the same day of each month having my hair cut by my beautiful assistant Jude (wifey) who fortunately knows only one style with the hair clippers, (as short as possible on a number 1. The hair was put in a tin and labelled for comparison over the months. We noticed that there was a gradual increase in hair mass and a darkening in colour, nothing spectacular but definitely a distinct favourable change. Several others balding people around me noticed that they had long hairs growing on top of their head, where previously they were completely bald.
It is fair to add that I have not recovered much in the way of lost hair since the start of 1994 when our bed was tilted, but it is also fair to add that I have more hair and colour than my brother who is 18 months younger, and who definitely had more hair and colour than me back in 1994.
I think we covered this before but it is worth mentioning again. Also with regards to a silver back gorilla. The silver back is the largest of the group, whose bulk becomes far greater than rivals while he runs the show. Around this time the hair follicles on his spine become lower in the centre of the spine due to the massive abdominal bulk and it’s weight distorting the spine as the gorilla walks and rests on all fours, evident by the pronounced curvature of the spine, (https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fwww.eurasiansafaris.com%2Fimages%2Fsilver-back.jpg&hash=e6014f2bbeeb0e79d43023fe9907850f)
which is also considerably less distorted on the smaller members of the group. Here we have an ideal situation to prove that colour of hair is maintained by gravity flowing freely through the vessels and dermis and epidermis and is compromised by gravity being unable to assist the circulation completely when the spine is dipped in the small of the gorilla back, whereas smaller males that have not developed the pronounced curvature of the spine remain unaffected from pigment loss in the hair follicles. (https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fwww.ugandatravelguide.com%2Fimages%2Fgorilla-pic1.jpg&hash=81dbd244f83bdeb63cb50735507e9c88)
Andrew K Fletcher
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Scary Gorilla Video
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Hello Guys,
I do not think that the rate of increase of hair in your body is equal,otherwise the hair at your eyebrow will also as long as your hair on head.The rate of gain of hair also depends on your health.In summer hair grows faster.For natural hair growth sun light is necessary.
Thanks
Mark
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"Long, beautiful, gleaming, steaming, flaxen, waxen... I adore hair! "
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I adore hair!
Really ? ...
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