skin and bones

Human Anatomy, Physiology, and Medicine. Anything human!

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Linn
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skin and bones

Post by Linn » Wed Feb 15, 2006 10:58 pm

:?:
What are the differences between light and dark skin as to handling temperature , and is it true that caucasin people have less dense or weaker bone?
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Post by baikuza » Thu Feb 16, 2006 2:57 am

about skin. dark is good for reptile which need heat to decompose the food which it eats, e.g. cobra..
so the process goes faster.

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Post by army » Thu Feb 16, 2006 7:36 am

What are the differences between light and dark skin as to handling temperature


dunno in the human...
s'far as I know, dark skin contains more melanine than the light one. Melanine is a device against UV ray from the sun. So darker skinned will be a bit safer from skin cancer. ark skin is likely an adaptation for a tropical people from exposion to sunlight.
:roll: let me analyze... :roll:

But, as we know in Physics, black body's temperature vary to the scale of blackness (0-1, 0=white,1=black) . The blacker a thing, the higher its temperature. It raises a problem to our body, because body needs certain range of temp. to live properly. Howeva, our body always sustain, by increasing the amount of evaporation.

It's likely so...

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Post by army » Thu Feb 16, 2006 7:37 am

I dunno 'bout the bone, i'm sorry... :cry:
Neva heard 'bout that

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Linn
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Post by Linn » Thu Feb 16, 2006 1:19 pm

skin color:
thanx for those answers


quote:
"dunno in the human...
s'far as I know, dark skin contains more melanine than the light one. Melanine is a device against UV ray from the sun. So darker skinned will be a bit safer from skin cancer. ark skin is likely an adaptation for a tropical people from exposion to sunlight.
let me analyze... "

yes, and I get freckles from the sun :cry:



How about this:
I have heard that polar bears are really black.

Since dark colors "absorb" the sun,
(if that is the reason) that makes sense to me.

However it wouldnt explain why darker skin people inhabit(ed) tropical, warm places and light skin were found in the colder regions.

except for the melanine and cancer protection. so polar bears must be dark for a different reason?

And about bone density in the three human types, I will google and see if I find that info if it excists. I wa being lazy and thought some one knew that one.

May be just an "urban tale" :lol:
Lynne


ok here is one for starters: now i remember about the bone density because I know caucasin woman ar more prone to ostioporosis:

http://www.niams.nih.gov/bone/hi/osteop ... _women.htm
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Post by Dr.Stein » Mon Feb 20, 2006 6:25 am

Dark skin is caused by distributed melanin contained by melanophore. This tone reflects UV penetration that is harmful to skin. People who live around equatorial areas have darker skin rather than any other places because sunlight, thus further UV, is very intensive an those areas.

Regarding to temperature regulation, this dark tone plays an important role in homeostasis, not to absorb a lot of energy from sunlight. Too much energy then leads to too much heat, then our body will respond to cool down with water praoduction that will lead to dehidration. This is a cascade reaction. If the first step or any step(s) is absent the cascade will not work. In this case, the first step is prevented (=absorbing too much energy).

About your second question, I have no idea by this moment. I'll try to find the fact later :)
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Post by i_r_e_d » Mon Feb 20, 2006 6:31 am

What about the dark Eskimo people? They're not subjected to much sunlight and yet they're pretty dark...
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Post by Dr.Stein » Mon Feb 20, 2006 11:42 am

You know where is the position of the sun towards the Earth? ;) You know the phenomenon called "Midnight Sun"? ;)

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