Sebaceous

Sebaceous glands are small oil-producing glands present in the skin of mammals. They are usually attached to hair follicles and release a fatty substance, sebum, into the follicular duct and thence to the surface of the skin. The glands are therefore part of the pilosebaceous unit, which consists of the hair follicle, hair shaft, and sebaceous gland. The sebum they produce helps to prevent the drying of the skin and hair, and also provides a layer of protection against microbial invasion.

Structure

Sebaceous glands are found throughout the skin except in the palms of the hands and soles of the feet. They are most abundant on the face and scalp, though they are distributed throughout all skin sites except the palms and soles. In the eyelids, meibomian sebaceous glands secrete a special type of sebum into tears. There are several related medical conditions, including acne, sebaceous cysts, hyperplasia, sebaceous adenoma and sebaceous gland carcinoma.

Function

Sebaceous glands secrete the oily, waxy substance called sebum (Latin: fat, tallow) that is made of triglycerides, wax esters, squalene, and metabolites of fat-producing cells. Sebum lubricates the skin and hair of mammals.

Clinical significance

Overactive sebaceous glands can produce too much sebum, contributing to oily skin, acne, and other skin problems. Conversely, underactive sebaceous glands can lead to dry skin and hair.

See also

• Acne
• Sebaceous cyst
• Sebaceous hyperplasia
• Sebaceous adenoma
• Sebaceous gland carcinoma

Sebaceous Resources
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