Hair
hideHair is a protein filament that grows through the epidermis from follicles deep within the dermis. The fine, soft hair found on many nonhuman mammals is typically called fur; wool is the characteristically curly hair found on sheep and goats. Found exclusively in mammals, hair is one of the defining characteristics of the mammalian class. Although other non-mammals, especially insects, show filamentous outgrowths, these are not considered "hair" in the scientific sense. So-called "hairs" (trichomes) are also found on plants. The projections on arthropods such as insects and spiders are actually insect bristles, composed of a polysaccharide called chitin. There are varieties of cats, dogs, and mice bred to have little or no visible fur. In some species, hair is absent at certain stages of life. The main component of hair fiber is keratin.
The hair can be divided into three parts length-wise, (1) the bulb, a swelling at the base which originates from the dermis, (2) the root, which is the hair lying beneath the skin surface, and (3) the shaft, which is the hair above the skin surface. In cross-section, there are also three parts, (1) the medulla, an area in the core which contains loose cells and airspaces (2) the cortex, which contains densely packed keratin and (3) the cuticle, which is a single layer of cells arranged like roof shingles.
For more information about Hair, read the full article at
Wikipedia.
This text uses material from Wikipedia and is available under the GNU Free Documentation License.
News tagged with hair
Studying hair of ancient Peruvians answers questions about stress
Other Sciences / Archaeology & Fossils
Dec 09, 2009 |
4 / 5 (3) |
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(PhysOrg.com) -- Recent studies show that one in three Canadians suffer from stress and the number is on the rise. But stress isn't a new problem.
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Accelerators and Light Sources of Tomorrow (Part 2: Accelerating with Light)
Dec 22, 2009 |
4.8 / 5 (6) |
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Accelerators are far from achieving the highest energies their builders aspire to, but size and cost may limit the kinds of facilities funding agencies can support. In the future, new kinds of machines will ...
Glitter-sized solar photovoltaics produce competitive results
Dec 22, 2009 |
4.4 / 5 (32) |
0
Sandia National Laboratories scientists have developed tiny glitter-sized photovoltaic cells that could revolutionize the way solar energy is collected and used.
Chemistry makes the natural 'wonder fabric' -- wool -- more wonderful
Nanotechnology / Nanomaterials
Dec 22, 2009 |
3 / 5 (1) |
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Scientists in China are reporting an advance that may improve the natural wonders of wool — already regarded as the "wonder fabric" for its lightness, softness, warmth even when wet, and other qualities. They ...
The next medical frontier: nano-surgery
Nanotechnology / Bio & Medicine
Dec 21, 2009 |
5 / 5 (5) |
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(PhysOrg.com) -- Engineering professor's nanorobot could be performing non-invasive surgical procedures on patients with tumors within the next decade.
Physicists propose quantum entanglement for motion of microscopic objects
Dec 21, 2009 |
4.3 / 5 (18) |
13
Researchers at the California Institute of Technology (Caltech) have proposed a new paradigm that should allow scientists to observe quantum behavior in small mechanical systems.
Christmas Web sales spike after snowstorm
Dec 21, 2009 |
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(AP) -- Stores in the snow-battered East Coast may have been sparse this weekend, but shoppers kept spending online. Retailers spurred sales with new discounts and shipping offers to make sure gifts arrive ...
Video game watchdog shuts down, victim of economy
Dec 18, 2009 |
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(AP) -- David Walsh said when he was assembling his first report card on video game violence 13 years ago, children were attacking on-screen monsters or aliens with imaginary chain saws and guns.
Gene linked to a rare form of progressive hearing loss in males is identified
Dec 17, 2009 |
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A gene associated with a rare form of progressive deafness in males has been identified by an international team of researchers funded by the National Institute on Deafness and Other Communication Disorders. The gene, PRPS1, ...
MO-SCI to manufacture SRNL's unique porous walled hollow glass microspheres
Nanotechnology / Nanomaterials
Dec 17, 2009 |
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A licensing agreement between the U.S. Department of Energy's Savannah River National Laboratory (SRNL) and specialty glass provider Mo-Sci Corporation will make SRNL's unique Porous Walled Hollow Glass Microspheres available ...
Brain surgery evolves to destroy rogue blood vessels
Dec 16, 2009 |
5 / 5 (1) |
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(PhysOrg.com) -- Over three decades, a world-recognized medical team at UC San Diego Medical Center has spurred the evolution of a complex surgery to destroy dangerous clusters of arteries and veins in the brain. Integrating ...
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