This link has been bookmarked by 25 people . It was first bookmarked on 03 Nov 2007, by someone privately.
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29 May 10
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wisdom teeth weren't always a cash crop for oral surgeons. Long ago, they served as a useful third set of meat-mashing molars. But as our brains grew our jawbone structure changed, leaving us with expensively overcrowded mouths.
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25 Feb 10
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29 Jan 10
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Though it makes up only 2 percent of our total body weight, the brain demands 20 percent of the body's oxygen and calories.
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All skin, without coloring, would appear creamy white. Near-surface blood vessels add a blush of red. A yellow pigment also tints the canvas. Lastly, sepia-toned melanin, created in response to ultraviolet rays, appears black in large amounts. These four hues mix in different proportions to create the skin colors of all the peoples of Earth.
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In addition to supporting the bag of organs and muscles that is our body, bones help regulate our calcium levels. Bones contain both phosphorus and calcium, the latter of which is needed by muscles and nerves. If the element is in short supply, certain hormones will cause bones to break downeupping calcium levels in the bodyeuntil the appropriate extracellular concentration is reached.
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We know that hormone-fueled changes in the body are necessary to encourage growth and ready the body for reproduction. But why is adolescence so emotionally unpleasant? Hormones like testosterone actually influence the development of neurons in the brain, and the changes made to brain structure have many behavioral consequences. Expect emotional awkwardness, apathy and poor decision-making skills as regions in the frontal cortex mature
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28 Feb 09
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26 Sep 08
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Thousands of Eggs Unused by Ovaries
When a woman reaches her late 40s or early 50s, the monthly menstrual cycle that controls her hormone levels and readies ova for insemination ceases. Her ovaries have been producing less and less estrogen, inciting physical and emotional changes across her body. Her underdeveloped egg follicles begin to fail to release ova as regularly as before. The average adolescent girl has 34,000 underdeveloped egg follicles, although only 350 or so mature during her life (at the rate of about one per month). The unused egg follicles then deteriorate. With no potential pregnancy on the horizon, the brain can stop managing the release of ova.
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17 Aug 08
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18 Jul 08
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30 Jun 08
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29 Jun 08
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23 Oct 07
fivekitten fivekittenInteresting facts Top 10 Things you didn't know about you and links to other top 10 from livescience.com
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04 Oct 07
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