|Schematic view of a hair follicle with sebaceous gland.|
|Cross-section of all skin layers.A hair follicle with associated structures. (Sebaceous gland labeled at center left.)|
|Gray's||subject #234 1069|
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 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.
The composition of sebum varies from species to species; in humans, the lipid content is as follows:
|16%||free fatty acids|
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.
A blocked sebaceous gland can result in a sebaceous cyst.
A condition involving enlarged sebaceous glands is known as sebaceous hyperplasia.
The prescription drug isotretinoin significantly reduces the amount of sebum produced by the sebaceous glands, and is used to treat acne.
neoplasm of the sebaceous glands.
Certain species of Demodex mites feed on sebum and are commonly found in the sebaceous glands of mammals, including those of humans.
The content of this section is licensed under the GNU Free Documentation License (local copy). It uses material from the Wikipedia article "Sebaceous glands" modified December 8, 2006 with previous authors listed in its history.