The primary function of sebaceous glands is to produce sebum, which serves multiple roles in maintaining the health of the skin and hair. The sebum produced by these glands acts as a natural moisturizer, preventing dryness and maintaining skin elasticity. Additionally, it forms a barrier on the skin, helping to reduce water loss and protect against harmful microorganisms. This oily secretion also helps to condition hair, making it shiny and preventing it from becoming brittle. Furthermore, the unique composition of sebum has antibacterial properties, which contribute to the skin's defense mechanism. By regulating the amount of sebum produced, sebaceous glands play a vital role in overall skin health and appearance.
Sebaceous glands are distributed throughout most areas of the skin, with higher concentrations found on the face, scalp, shoulders, and upper back. They are closely associated with hair follicles; each gland is usually attached to a follicle, from which sebum is secreted onto the surface of the skin. In some regions, such as the palms of the hands and soles of the feet, sebaceous glands are absent, while they are numerous in areas like the face and scalp where the skin is oilier. In terms of anatomical positioning, these glands lie within the dermis, the deeper layer of the skin, and extend toward the epidermis, allowing their secretion to reach the outer surface effectively.