What is the primary function of sebaceous glands in the skin?

The primary function of sebaceous glands in the skin is to secrete sebum, an oily substance that helps lubricate the skin and hair. Sebum plays a crucial role in maintaining skin hydration and barrier function, making the skin less prone to dryness and irritation. By providing this natural oil, sebaceous glands contribute to the skin's elasticity and overall health.

Moreover, sebum has antimicrobial properties that can help protect the skin from infections by creating an unfavorable environment for harmful bacteria. This lubrication is particularly important in areas with a high density of hair follicles, as it keeps the hair moisturized and supports healthy hair growth.

The other functions mentioned do not relate directly to the action of sebaceous glands. Sweat production is the role of sweat glands, while nutritional support for hair follicles and heat generation can be attributed to different physiological mechanisms.