The primary role of sebaceous glands is to:

Sebaceous glands play a crucial role in maintaining the health and integrity of the skin by secreting sebum, which is an oily substance. This secretion is essential for several reasons. Primarily, sebum helps to lubricate the skin and hair, preventing dryness and brittleness. It also serves as a barrier to protect the skin from external irritants and pathogens, creating a thin film that combats environmental factors. Additionally, sebum has antimicrobial properties, helping to reduce the risk of infections on the skin's surface.

While other bodily processes are essential for overall skin health, such as temperature regulation or nutrient provision, those functions are not carried out by sebaceous glands. Similarly, the absorption of vitamin D occurs primarily through the skin's exposure to sunlight, rather than through the action of sebaceous glands. Thus, the secretion of sebum stands out as the primary and specific role of these glands in skin physiology.