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sebaceous gland

Did you mean: sebaceous gland (in anatomy), sebaceous

 
Dictionary: sebaceous gland
 

n.

Any of various glands in the dermis of the skin that open into a hair follicle and produce and secrete sebum.


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Sci-Tech Encyclopedia: Sebaceous gland
 

A gland which produces and liberates sebum, a mixture composed of fat, cellular debris, and keratin. When the gland arises in association with a hair follicle, it forms a thickened outpushing from the side of the developing follicle near the epidermis. Central cells in these sebaceous glands form oil droplets within the cytoplasm. These cells disintegrate to liberate the sebaceous substance and are therefore of the holocrine type. The Meibomian or tarsal glands, within the tarsus or supporting plate at the edge of the eyelids, are sebaceous and complex tubuloacinous structures. The numerous separate glands open along the entire edge of the upper and lower lids. Retained secretions of the tarsal glands produce a chalozion or Meibomian cyst. See also Gland.


 
Dental Dictionary: sebaceous glands
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(sēbā′shəs)
n.pl

Exocrine glands of the skin, many of which open into the hair follicles and secrete an oily substance that coats the hair and surrounding epithelium, helping to prevent evaporation of sweat and retain body heat. In the oral cavity, these glands are known as Fordyce’s granules or Fordyce’s spots and can be seen with the unaided eye as yellowish-white in color and are more common in older adults on the buccal and labial mucosa.

 
Britannica Concise Encyclopedia: sebaceous gland
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Small oil-producing gland in the skin, usually connected to a hair follicle by a duct into which it releases sebum, a component of the slightly greasy film on the skin that helps keep it flexible and prevents too much water loss or absorption. The glands are distributed over the entire body except the palms and soles, most abundantly on the scalp and face. Large and well developed at birth, they shrink during childhood but enlarge again and increase their sebum output at puberty (apparently in response to male hormones), often leading to acne.

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Columbia Encyclopedia: sebaceous gland
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sebaceous gland (səbā'shəs) , gland in the skin of mammals that secretes an oily substance called sebum. In humans, sebaceous glands are primarily found in association with hair follicles but also occur in hairless areas of the skin, except for the palms of the hand and soles of the feet. Sebum is a mixture of fat and the debris of dead fat-producing cells. These cells are constantly replaced by new growth at the base of the glands. Generally the sebum is deposited on the hairs inside the follicles and is brought up to the surface of the skin along the hair shaft. In hairless areas, the sebum surfaces through ducts. Sebum lubricates and protects the hair and skin and prevents drying and irritation of membranes. Sebum may collect excessively as a result of poor hygiene, a diet rich in fats, or accelerated glandular activity, especially during adolescence. Excessive secretions of sebum may be related to acne, certain forms of baldness, and other skin disorders.


 
Health Dictionary: sebaceous glands
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(si-bay-shuhs)

Glands located in the skin that secrete an oily substance, sebum. Sebum lubricates the skin and hair.

  • Clogged sebaceous glands can result in pimples.

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    Wikipedia: Sebaceous gland
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    Sebaceous glands are microscopic glands in the skin which secrete an oily matter (sebum) in the hair follicles to lubricate the skin and hair of animals. In humans, they are found in greatest abundance on the face and scalp, though they are distributed throughout all skin sites except the palms and soles.[1] The extreme use (up to 10 times doctor prescribed amounts) of anabolic steroids by bodybuilders for muscle gain and repartitioning effects tend to stimulate the sebaceous glands which can cause acne.[2]

    Sebum can also build up around body piercings.[3]

    Contents

    Sebum composition

    The composition of sebum varies from species to species; in humans, the lipid content is as follows:[4]

    Percent composition Substance
    25% wax monoesters
    41% triglycerides
    16% free fatty acids
    12% squalene

    Additional images

    See also

    References

    External links


     
     

    Did you mean: sebaceous gland (in anatomy), sebaceous


     

    Copyrights:

    Dictionary. The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2007. Published by Houghton Mifflin Company. All rights reserved.  Read more
    Sci-Tech Encyclopedia. McGraw-Hill Encyclopedia of Science and Technology. Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved.  Read more
    Dental Dictionary. Mosby's Dental Dictionary. Copyright © 2004 by Elsevier, Inc. All rights reserved.  Read more
    Britannica Concise Encyclopedia. Britannica Concise Encyclopedia. © 2006 Encyclopædia Britannica, Inc. All rights reserved.  Read more
    Columbia Encyclopedia. The Columbia Electronic Encyclopedia, Sixth Edition Copyright © 2003, Columbia University Press. Licensed from Columbia University Press. All rights reserved. www.cc.columbia.edu/cu/cup/  Read more
    Health Dictionary. The New Dictionary of Cultural Literacy, Third Edition Edited by E.D. Hirsch, Jr., Joseph F. Kett, and James Trefil. Copyright © 2002 by Houghton Mifflin Company. Published by Houghton Mifflin. All rights reserved.  Read more
    Wikipedia. This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Sebaceous gland" Read more