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cmg
November 13th, 2011, 08:07 PM
Hi everyone! I snipped this quote from another thread, hope you don't mind, ktani:


(Quotation from
http://www.pgbeautygroomingscience.com/hair-types.html )

"All hair, even the apparently perfectly straight hair of Asian people, twists as it grows. The number of twists in a given length of hair determine how curly it is: the more twists there are, the curlier it will be. Some African hair has 12 times as many twists per centimetre as Caucasian hair."
I have been wondered about this. I have very twisted hair, but I always put that down to heat damage. I mean twists like "Turning torso" here. I am alittle skeptic about the statement this would affect the overall curliness, having had some poeples hairs under the microscope in my work. I recall at least two samples that were "perfectly straight" under the microscope, but they had (naturally) curly hair. It is not a big stretch to believe it's this way though. It could work like something of the "twisting a rope hard"-effect. Twist it hard enough, and it starts coiling up. But where is the fixed pressure on hair? Any opinions or thoughts on this?

missdelarocha
November 13th, 2011, 08:19 PM
That's very interesting, I agree with your rope reference but am still not sure, I suppose it makes sense but I don't think it's going to turn out to be fact.

ETA:
http://www.lifeslittlemysteries.com/what-makes-hair-curly-0255/
According to another site the amount of disulphide bonds is what causes curls, that might be what they're talking about (in the site linked above) when they say "Scientists once thought that the curliness of hair was determined by the individual hair shafts" though.

dawnrader
November 13th, 2011, 08:22 PM
The only fixed pressure i can think of that would be on hair would be gravity pulling it towards the centre of the earth. Certainly nothing to make it twist. As far as i was aware having curly hair was to do with abnormal hair follicles.

CurlyCap
November 13th, 2011, 08:35 PM
As far as i was aware having curly hair was to do with abnormal hair follicles.

Not so much abnormal. Just different.

I've always liked this explanation, because it's something we've all done. I always wanted to try the part where you run your nails down a piece of straight hair, but I don't have anyone to ask. And collecting a straight hair is...creepy. :D

http://www.education.com/science-fair/article/curly/

CurlyCap
November 13th, 2011, 08:41 PM
Twist it hard enough, and it starts coiling up.

I always wondered about this.

There are two ways to get super defined curls (not product based)in those of us with natural curls:

1. Doodles: Take a clump of hair and wrap it around your finger, like you're forming a spring out of your hair. Smooth the final product and slip your hair off your finger. Voila! instant perfect (and indestructible) curl.

2. TWISTING: Never understood this. I'm sure there's some physics to it. But if you take a clump near the scalp, smooth it so all the hairs line up, and then twist it moving the from the scalp down, you get a perfect sausage curl.

However, when I read that curly hair has more twists as it comes of out of the scalp, I'm always like "Duh. It's curling as it grows!" Maybe it's more complicated that than that though.:poot:

cmg
November 13th, 2011, 08:58 PM
I cinda subscribed to this theory, to some extent: "Scientists once thought that the curliness of hair was determined by the individual hair shafts" I find the sulfide bonds theory being alittle far fetched but not impossible. Fingernails that grow long usually curl too. The curl does not happen in the hair or should I say nail. Curvature is detectable as soon as the nail leaves the skin, indicating something happens already there. Have you seen theese meter-long nails? Some are really scary.

Somewhere I read also that curliness might be influenced by the angle in which it grows out of the skin. Many of my hairs grow in a low angle, making plucking eye brows difficult for example. Hmm...

holothuroidea
November 13th, 2011, 09:03 PM
I always thought that the curliness of the hair was due to the frequency of disulphide bonds in the protein that makes up the hair shaft.

What I've always wondered is why hair texture changes over time or after hormonal changes. My hair was 1a until I had my first baby and BOOM waves come out of nowhere. I'm not the only person this has happened to. Some people are born with curls and then they disappear after their first cut. Some people have wavy hair until puberty and it turns into ringlets.

So what exactly dictates the frequency of our disulphide bonds? Maybe there is more than one contributing factor to curly hair.

Very interesting topic, cmg!

holothuroidea
November 13th, 2011, 09:09 PM
I find the sulfide bonds theory being alittle far fetched but not impossible.

I learned this in biochem (and can you believe I payed attention? :D). It was not presented to me as a theory. We were learning about protein structures and what gives them their shape. When disulphide bonds came up the teacher said "this is why hair curls." And we all nodded and said "ah-ha."

Biochem teachers have been known to be wrong. ;)

missdelarocha
November 14th, 2011, 03:53 AM
The curl does not happen in the hair or should I say nail. Curvature is detectable as soon as the nail leaves the skin, indicating something happens already there. Have you seen theese meter-long nails? Some are really scary.

Yes haha I've seen them! It's interesting because the bend makes for appealing and strong nails but it doesn't occur to most people that eventually this would lead to curling. I wonder what mine would do, they're rather flat haha.


Somewhere I read also that curliness might be influenced by the angle in which it grows out of the skin. Many of my hairs grow in a low angle, making plucking eye brows difficult for example. Hmm...


I wonder if eyebrows were able to grow longer would they would curl :p? Though maybe they're round not oval and the follicle is actually at an angle, because according to another link posted the object wants to bend towards it's flatter side, which suggests one side of the single curly hair is flatter but not necessarily growing out from the follicle at an angle.

Weeeeerrrryyy intewesting. :hmm:

luxepiggy
November 14th, 2011, 06:37 AM
Curly hair is characterized by asymmetric keratinization of the cortical cells - basically, the two sides of the hair are keratinized at slightly different rates. The hair curls in the direction of the slower growing side; the greater the asymmetry, the curlier the hair (http://onlinelibrary.wiley.com/doi/10.1111/j.1365-4632.2007.03454.x/abstract)

chou
November 14th, 2011, 07:42 AM
Curly hair is characterized by asymmetric keratinization of the cortical cells - basically, the two sides of the hair are keratinized at slightly different rates. The hair curls in the direction of the slower growing side; the greater the asymmetry, the curlier the hair (http://onlinelibrary.wiley.com/doi/10.1111/j.1365-4632.2007.03454.x/abstract)

This is very interesting. Makes the most sense to me.

I'm reading the section on curly hair on Wikipedia right now and it's super racist, confusing, and poorly cited. Look at this : "By contrast, some intuit that tightly coiled hair that grows into a typical Afro-like formation would have greatly reduced the ability of the head and brain to cool. They reason that although hair density in African peoples is much less than their European counterparts, in the intense sun the effective 'woolly hat' produced would have been a disadvantage."

People at LHC know way more about hair science than the weirdo who wrote that piece of trash.

Madora
November 14th, 2011, 08:23 AM
Per "George Michael's Secrets for Beautiful Hair" (Doubleday 1981) pg 7:

The pattern of cell growth at the papilla, for example, will determine whether you have straight, wavy, or curly hair. Straight hair, of course, is the most common, but when the growth pattern of the papilla is uneven the result will be curly hair.

ktani
November 14th, 2011, 08:51 AM
cmg
No, I do not mind at all.
Hope this helps - colour added by me - 2007
http://www.nature.com/jidsp/journal/v12/n2/pdf/5650047a.pdf
"BASIC PRINCIPLES OF HAIR SHAFTS AND RACE
The African-American hair shaft is elliptical or flattened in cross-section and spiral or tightly curled in tertiary structure (Syed et al., 1995). Within the black race, significant variations may be seen, but in most African Americans, the curled hair does not emanate from a straight follicle. Instead, the follicle where the hair is formed is just as curved as the hair itself (Lindelof et al., 1988 ). ... Bernard (2003) performed in vitro experiments comparing the growth of curly and straight hair. He found that curled hairs dissected out of the scalp and placed in culture continued to grow in curled fashion, suggesting that the shape of the hair may be intrinsically programmed by the lower half of the hair follicle with or without the usual dermal environment. ...There also appears to be less moisture in the hair shaft of African patients than in Caucasians. ...


ETA:
These authors compared cystine-rich protein distribution in the hair of black Africans to Causcasian and Asian hair using transmission electron microscopy and silver stains (Khumalo et al., 2005). The results showed similar distribution of cystine-rich proteins in all ethnicities, suggesting that the excessive structural damage observed in African hair shafts is consistent with physical trauma and/or, as yet, undiscovered other structural abnormalities and not a trichothiodystrophy-like process."

ktani
November 14th, 2011, 09:25 AM
Explanation with illustrations - colour added by me
http://www.bio.davidson.edu/courses/genomics/2011/Piper/Background.html
"In general everyone's hair contains the same basic keratin filaments, which have the potential to form the disulfide bonds necessary for curly hair. The difference between curly hair and straight hair is the shape of the shaft of hair. A very round shaft allows less disulfide bonds, and those that are present are in line with one another, resulting in straight hair. The flatter the hair shaft becomes, the curlier hair gets, because the shape allows more cysteines to come in contact with one another and form the necessary disfulfide bridges. ...

ETA: Folicle shape determines hair texture" See pictures under text

References
http://www.bio.davidson.edu/courses/genomics/2011/Piper/Conclusions.html

holothuroidea
November 14th, 2011, 02:32 PM
Explanation with illustrations - colour added by me
http://www.bio.davidson.edu/courses/genomics/2011/Piper/Background.html
"In general everyone's hair contains the same basic keratin filaments, which have the potential to form the disulfide bonds necessary for curly hair. The difference between curly hair and straight hair is the shape of the shaft of hair. A very round shaft allows less disulfide bonds, and those that are present are in line with one another, resulting in straight hair. The flatter the hair shaft becomes, the curlier hair gets, because the shape allows more cysteines to come in contact with one another and form the necessary disfulfide bridges. ...

ETA: Folicle shape determines hair texture" See pictures under text

References
http://www.bio.davidson.edu/courses/genomics/2011/Piper/Conclusions.html

So... my hair shafts got flatter when I had a baby? I wonder what the mechanism for that is.

holothuroidea
November 14th, 2011, 02:35 PM
I'm reading the section on curly hair on Wikipedia right now and it's super racist, confusing, and poorly cited. Look at this : "By contrast, some intuit that tightly coiled hair that grows into a typical Afro-like formation would have greatly reduced the ability of the head and brain to cool. They reason that although hair density in African peoples is much less than their European counterparts, in the intense sun the effective 'woolly hat' produced would have been a disadvantage."

People at LHC know way more about hair science than the weirdo who wrote that piece of trash.

Regardless of how racist it might be, it doesn't make any kind of sense.

I imagine that hair 10 inches long doesn't actually insulate your head more than hair that is 1 inch long. I always thought hair that grew into an afro had an advantage in the heat, because it stays up off the neck and shoulders. Even my thin fine hair can be hot in the summer when it's on my neck!

holothuroidea
November 14th, 2011, 02:44 PM
Two articles sited here have compared hair on the basis of race and that doesn't really work, does it?

First, you have the fact that race is defined by subjective and often arbitrary standards. If you go by ethnicity it doesn't work either. The ethnicity of African-Americans is different from Ethiopians but they could have the same hair texture. But even if you look past all of this- not all people of the same race or ethnicity have the same hair type! I've known black people whose hair is naturally in the 3's, and people we'd classify as caucasian who are clearly 4's.

I don't know why these researchers don't just study the difference between straight and curly. Race is really irrelevant.

ktani
November 14th, 2011, 02:52 PM
So... my hair shafts got flatter when I had a baby? I wonder what the mechanism for that is.

Here you go and yes, possibly, lol - colour added by me
http://www.npr.org/templates/story/story.php?storyId=102074149
"An Influence From Hormones?
After all, hair changes in other ways during adolescence or after having a baby, two events that generate hormonal changes in the body.
"Hormones are a logical guess but I have no evidence to prove that," says Dr. Val Randall, an endocrinologist at the University of Bradford in England.
Randall is one of the few people doing research on hormones and hair. She says it is difficult to figure something like this out because it doesn't happen very often.
But, says Randall, change is possible because hair is always replacing itself:
"The hair that you have on your head age 10 is not the hair that you have on your head age 2, and it is not the hair you have on your head age 50," Randall says. If the new follicles grow back a different shape, then your new hair will be different, too."

holothuroidea
November 14th, 2011, 03:14 PM
But, says Randall, change is possible because hair is always replacing itself:
"The hair that you have on your head age 10 is not the hair that you have on your head age 2, and it is not the hair you have on your head age 50," Randall says. If the new follicles grow back a different shape, then your new hair will be different, too."

Hey thanks, Ktani!

The funny thing about that is I had a major shed before it changed. Like loosing wads of hair major.

I've had another major shed after my second baby, too, that just ended a month ago. Now I've got tons of baby hairs growing in. I wonder if they'll be wurlier!! I hope so :D

cmg
November 14th, 2011, 04:00 PM
No we are getting somewhere! Some interesting explanation models.

I dont think it has to do with racism, this is besides the point. We as a human race are a product of our environment. Mutations are successful or not successful, depending on how they work out in a specific surrounding. Everything about our appearance is a result of mutations. Successful mutations become permanented because more of these individuals survive, and the chance for them to meet someone else with the same mutation and breed successfully increases. After some time this creates a genepool locally in a favourable environment. In modern times, we are more and more independent of these favourable environments. We have the ability to control our housing climate, food accessibility throughout the seasons and transportation of food and other necessities, like clothing. This has all changed. And we interbreed while we move around all over the world. This increases with the global density of the population. So I dont think the scientists are too far off thinking in those terms. We have to use this criteria for our investigations, including prehistoric and historic samples from different localities. Emotional sentiments have very little value, this has to be totally unbiased and without regard for hurting somebodys feelings etc. This has to include all sorts of theories though, not favouring one in particular or excluding another. If the theory is not investigated, we will also never know if it is wrong or not.

Winged
November 14th, 2011, 04:07 PM
I've always liked this explanation, because it's something we've all done. I always wanted to try the part where you run your nails down a piece of straight hair, but I don't have anyone to ask. And collecting a straight hair is...creepy. :D

http://www.education.com/science-fair/article/curly/

It totally works! I just did it to a strand of my hair and it curled. Kinda like curling the ribbon on a present. :D

ktani
November 14th, 2011, 04:29 PM
Hey thanks, Ktani!

The funny thing about that is I had a major shed before it changed. Like loosing wads of hair major.

I've had another major shed after my second baby, too, that just ended a month ago. Now I've got tons of baby hairs growing in. I wonder if they'll be wurlier!! I hope so :D

You are very welcome.

I agree with cmg. It is about looking at the most curly hair and African hair has other characteristics which makes it of interest to scientists.

It is not about race. It is about a type of hair.

Is that type of hair also found in Europeans? Yes, because we are all a mix of DNA. The "purest" form of it can be found in Africans, no racism intended at all.

cmg
November 14th, 2011, 05:04 PM
Reading about curling the ribbons on a present made me cringe. Imagine doing this to head hairs :scared:Iiiih

CurlyCap
November 14th, 2011, 05:22 PM
It totally works! I just did it to a strand of my hair and it curled. Kinda like curling the ribbon on a present. :D

SWEET! Thanks for posting that! I've wondered for literally years.

Now, if someone could figure out a temporary non-damaging way to do that....bucku buckos man. :D

cmg
November 14th, 2011, 05:53 PM
Ha ha :D
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holothuroidea
November 14th, 2011, 07:42 PM
No we are getting somewhere! Some interesting explanation models.

I dont think it has to do with racism, this is besides the point. We as a human race are a product of our environment. Mutations are successful or not successful, depending on how they work out in a specific surrounding. Everything about our appearance is a result of mutations. Successful mutations become permanented because more of these individuals survive, and the chance for them to meet someone else with the same mutation and breed successfully increases. After some time this creates a genepool locally in a favourable environment. In modern times, we are more and more independent of these favourable environments. We have the ability to control our housing climate, food accessibility throughout the seasons and transportation of food and other necessities, like clothing. This has all changed. And we interbreed while we move around all over the world. This increases with the global density of the population. So I dont think the scientists are too far off thinking in those terms. We have to use this criteria for our investigations, including prehistoric and historic samples from different localities. Emotional sentiments have very little value, this has to be totally unbiased and without regard for hurting somebodys feelings etc. This has to include all sorts of theories though, not favouring one in particular or excluding another. If the theory is not investigated, we will also never know if it is wrong or not.

Hm. I never thought it was racist. I just thought it was curious because race is really irrelevant. They should be segregating based on hair type and not race because hair type is not necessarily dependent on race or ethnicity. If you want to investigate evolutionary anthropology and why certain ethnicities developed adaptations for various environments that's a whole other study and is really not related to why curly hair is curly and straight hair is straight.

Anyway, just making an observation.

Winged
November 14th, 2011, 07:52 PM
SWEET! Thanks for posting that! I've wondered for literally years.

Now, if someone could figure out a temporary non-damaging way to do that....bucku buckos man. :D

That'd be nice. It would be sooo easy to curl my hair. The strand I did was very curly when I did it.

holothuroidea
November 14th, 2011, 08:54 PM
I tried the fingernail thing. My hair didn't really curl it just got all kinky and wiry looking.

As my DH so eloquently put it, "It looks like a pube." :D

I tried to take a picture of it by putting it up against a piece of white paper but apparently my hair is too fine to photograph with a 12.2 mega pixel camera. :rolleyes:

ETA: Winged, you list your hair texture as medium. That probably makes a difference. I imagine that it's equivalent to stripping the "scale" part of the hair off of one side so it curls in on itself. Since I have so very little of that in my hair strands to begin with taking any off just destroys it. I wonder if this is why very fine very curly hair tends to be dry. Less protective coating.

cmg
November 15th, 2011, 07:47 PM
Just throwing in a hair picture. Its the hair from a coworker of mine. He is georgeous, with his classic length light/medium blonde hair. Enlargement 100x. Hairtype is 1a/1b something and untreated. Some greys present, this is a blonde hair still containing melanin.

The hair looks quite healthy, full of pigment, ropey, so i guess its medium thickness. This particular strand was telogen, but there is no direct difference in the picture to tell this, I'm just mentioning it.

http://forums.longhaircommunity.com/picture.php?albumid=9119&pictureid=118958

I will try to find a picture showing the aforementioned twists. It shows up on my own hair but I haven't got a clear enough picture of this.

cmg
November 15th, 2011, 08:52 PM
Two more pictures from the same subject are available in my album, one in 3D-filtering with a very rare oval shaped strand in the middle (rare for this type hair).

For comparison: Hairsample from female, curly hair that is henna treated. The color is like dark oxidized copper, in the medium/dark blonde range. Nearly no melanin present (not in this sample anyway). 100x enlargement, same lightening conditions as the previous blonde untreated male hairsample.

First picture shows the hair from the side = this sample has oval hair strands. The white blotches top and center are starch from Aloe Vera gel. The dark fibre to the right can be used as a marker. The dye and intrinsic color seem evenly distributed, indicating almost every part of the surface is coated with the henna dye.

http://forums.longhaircommunity.com/picture.php?albumid=9119&pictureid=118961

Next picture shows the same sample turned around 90 degrees. The visual diameter changes, which indicates an oval shape. It also reveals longitudial darker and lighter edges. This pigment distribution is typical of both dyed and natural hair. It is not a photoeffect because of focusing. The darker part is not from the henna. This darker edge will visually get smoothed out and blend in whith the lighter edge when more henna is put on the hair or if it gets coated with products or dirt. This darker edge is due to pigment distribution inside the hair, the henna does not get in there but will coat the hair strand evenly on the outer parts and thus conceal the color difference. If this hair had been undyed, it would have been more transparent and the dark edge clearly visible. The henna deposits in blotches, getting more and more densly distributed with increasing number of treatments.

http://forums.longhaircommunity.com/picture.php?albumid=9119&pictureid=118962

These pictures do not so much reveal the texture of the hair I think. I will think of a better way to show this. Sample 1 was ropey and round in diameter, typically scandinavian hair. Within the sample some very few oval hairs are present, less than 0,5%. The second sample was oval shaped curly hair of mixed racial origin. Almost all hairs in this sample have oval diameter shape. The twisting was not visible in these pictures, though existent whithin the sample.

missdelarocha
November 19th, 2011, 07:11 PM
Cmg that's so cool, thank you!