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 |
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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.
Single gene may cause curly hair
Nov 10, 2009 |
4.4 / 5 (8) |
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(PhysOrg.com) -- Scientists in Australia have identified a single gene that strongly influences whether you have curly or straight hair.
Ancestry attracts, but love is blind
Nov 20, 2009 |
4 / 5 (1) |
1
People preferentially marry those with similar ancestry, but their decisions are not necessarily based on hair, eye or skin colour. Research, published in BioMed Central's open access journal Genome Biology, shows that M ...
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Students Hone Engineering Skills in Robotics
22 hours ago |
5 / 5 (1) |
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(PhysOrg.com) -- Robots have fascinated future engineers for generations. Recently, a group of young students had an opportunity to design and build their own robots using LEGOs, the popular plastic pieces ...
What's the best hangover cure? Truth be told, there isn't one
Dec 09, 2009 |
2.5 / 5 (2) |
13
(PhysOrg.com) -- With the holiday party season at hand, UNC's Dr. James C. Garbutt offers these tips about how to enjoy a few drinks responsibly -- while sparing yourself and those around you from the potentially ...
Prof gets messages from space
Space & Earth / Space Exploration
Dec 08, 2009 |
4.3 / 5 (6) |
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(PhysOrg.com) -- Barbara Frisken received several messages from outer space this year on her answering machine.
Study reveals how Arctic food webs affect mercury in polar bears
Dec 08, 2009 |
3 / 5 (2) |
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With growing concerns about the effects of global warming on polar bears, it's increasingly important to understand how other environmental threats, such as mercury pollution, are affecting these magnificent Arctic animals.
Small addition to cancer drug may make big difference
Dec 08, 2009 |
3 / 5 (2) |
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University of Florida researchers have found a way to use just a fraction of the normal dosage of a highly toxic, debilitating chemotherapy drug to achieve even better results against colon cancer cells.
Elusive protein points to mechanism behind hearing loss
Medicine & Health / Neuroscience
Dec 08, 2009 |
5 / 5 (1) |
0
(PhysOrg.com) -- A serendipitous discovery of deaf zebra fish larvae has helped narrow down the function of an elusive protein necessary for hearing and balance. The work, led by Rockefeller University’s A. ...
Research is shattering traditioinal notions of laser limits
Dec 07, 2009 |
5 / 5 (2) |
1
Air Force Office of Scientific Research and National Science Foundation-funded professor, Dr. Xiang Zhang has demonstrated at the University of California, Berkeley the world's smallest semiconductor laser, ...
Nobel winners helped by independence, coffee
Dec 07, 2009 |
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(AP) -- Intellectual freedom, independent research and frequent coffee breaks with colleagues helped this year's Nobel Prize winners make their groundbreaking scientific discoveries.
White, but not pure
Dec 07, 2009 |
4.7 / 5 (3) |
3
Even the snow on Aconcagua Mountain in the Andes is polluted with PCBs. An international team of researchers detected low concentrations of these toxic, carcinogenic chlorine compounds in samples taken from ...
Researchers identify new stem cell
Dec 07, 2009 |
5 / 5 (4) |
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(PhysOrg.com) -- Scientists have discovered a new type of stem cell in the skin that acts surprisingly like certain stem cells found in embryos: both can generate fat, bone, cartilage, and even nerve cells. These newly-described ...
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