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Defintion of Sebaceous Glands
Sebaceous Glands is the small glands that produce sebum, a lipid-based, oily fluid that lubricates the surface of the skin. Sebum is mostly the metabolic waste that remains after fat cells break down.
Most sebaceous glands empty into hair follicles, secreting sebum along the emerging hair shaft. Some sebaceous glands exist independent of hair follicles and secrete sebum directly to the skin’s surface, such as those on the glans of the penis.
The palms of the hands and the soles of the feet are the only skin surfaces that do not have sebaceous glands.
The oily consistency of sebum gives the skin a highly water-resistant coating. The lubricating qualities of sebum keep the keratinocytes, the cells that make up the epidermis, supple and flexible.
Without adequate lubrication the skin becomes dry and the keratinocytes scale and flake, presenting not only an undesirable cosmetic appearance but also compromising the skin’s resistance against pathogenic (disease-causing) microorganisms.
Sebum also helps regulate the skin’s natural flora, the collective of bacteria, yeasts, and other microscopic organisms that inhabit the epidermis. These microorganisms draw nutrients from the lipids in the sebum.
For further discussion of the sebaceous glands within the context of integumentary structure and function, please see the overview section, “The Integumentary System.”
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