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The sebaceous glands are glands found in the skin of mammals.
Sebum
Sebaceous glands secrete an oily substance called sebum (Latin, meaning fat or tallow) that is made of fat (lipids) and the debris of dead fat-producing cells. In the glands, sebum is produced within specialized cells and is released as these cells burst; sebaceous glands are thus classified as holocrine glands.
Sebum is odorless, but its bacterial breakdown can produce odors. Sebum is the cause of some people experiencing "oily" hair if it is not washed for several days. Earwax is partly sebum.
Function
Sebum acts to protect and waterproof hair and skin, and keep them from becoming dry, brittle, and cracked. It can also inhibit the growth of microorganisms on skin.
Composition
The composition of sebum varies from species to species; in humans, the lipid content is as follows:[1]
Percent composition Substance
25% wax monoesters
41% triglycerides
16% free fatty acids
12% squalene
Locations of glands
A branched type of acinar gland, these glands exist in humans throughout the skin except in the palms of the hands and soles of the feet.
Sebaceous glands can usually be found in hair-covered areas where they are connected to hair follicles to deposit sebum on the hairs, and bring it to the skin surface along the hair shaft. The structure consisting of hair, hair follicle and sebaceous gland is known as pilosebaceous unit.
Sebaceous glands are also found in non haired areas of lips, eyelids, penis, labia minora and nipples; here the sebum reaches the surface through ducts. At the rim of the eyelids, meibomian glands are a specialized form of sebaceous gland that secrete sebum into the tears coating the eye to prevent evaporation.
Changes in life cycle
The sebaceous glands of a human fetus in utero secrete a substance called Vernix caseosa, a "waxy" or "cheesy" white substance coating the skin of newborns.
The activity of the sebaceous glands increases during puberty because of heightened levels of androgens. In males, sebaceous glands begin to appear predominantly on the penis during and after puberty. This is however normal, not to be confused with an STD. In females, they appear predominantly in the labia minora.
Pathology
Sebaceous glands are involved in skin problems such as acne and keratosis pilaris. The prescription drug isotretinoin significantly reduces the amount of sebum produced by the sebaceous glands, and is used to treat acne.
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]
A blocked sebaceous gland can result in a sebaceous cyst.
A condition involving enlarged sebaceous glands is known as sebaceous hyperplasia.
Sebaceous gland carcinoma is a rare and aggressive form of cancer involving the sebaceous glands; sebaceous adenoma is a more benign neoplasm of the sebaceous glands.
Importance to other animals
Certain species of Demodex mites feed on sebum and are commonly found in the sebaceous glands of mammals, including those of humans.
The preputial glands of mice and rats are large modified sebaceous glands that produce pheromones.

2007-01-30 10:13:35 · answer #1 · answered by Anonymous · 0 1

Sebaceous gland, a gland in the skin which secretes oily matter (sebum) into the hair follicles to lubricate the skin and hair.

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. The second link provides more information and diagrams.

2007-01-31 22:31:43 · answer #2 · answered by Anonymous · 0 0

sabaceous cells are those which secrete oil. They are found in the integumentary system like hair follicles etc.

2007-01-30 08:09:12 · answer #3 · answered by Anonymous · 0 0

Not sure about the biology, but I know that a lot of men and women have them on their genitals. A lot of people freak out about them, but they are totally harmless. My issue down there used to be dry skin, and the only thing that keeps it moisturized is a penis health creme. These are way better than any lotion or ointment because they are made just for the penis skin. Good stuff.

2015-11-25 06:57:24 · answer #4 · answered by Anonymous · 0 0

I had a sabaceous cyst on my head.It was removed and taken for biopsy to see if it had cancer cells.Its a skin cell that mutates.

2007-01-30 07:26:37 · answer #5 · answered by Anonymous · 0 0

sebaceous cells produce sebum or oils, they are found on the skin surface including the scalp. Inflammation of sebaceous cells is what causes acne and blackheads

2007-01-30 07:58:39 · answer #6 · answered by MLstar 2 · 0 0

I think you mean sebaceous cell. They are glands that secrete sebum, most commonly found on the scalp.

There is more info and some good diagrams on wikipedia. See link below.

http://en.wikipedia.org/wiki/Sebaceous

2007-01-30 07:27:51 · answer #7 · answered by queenbee 3 · 0 0

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