What structures are connected to hair follicles and produce oil for the skin?

Sebaceous glands are specialized glands directly associated with hair follicles, and they play a crucial role in producing an oily substance known as sebum. This oil helps to moisturize and protect both the hair and the skin, preventing them from drying out and becoming brittle. The secretion of sebum also helps to maintain the skin's barrier function and has an antimicrobial effect, which contributes to overall skin health.

Sweat glands, eccrine glands, and apocrine glands are distinct types of glands with different functions. Eccrine glands primarily regulate body temperature through sweat production, while apocrine glands are associated with hair follicles and contribute to body odor through the secretion of a thicker, protein-rich sweat. Neither of these types of glands produces the oil that sebaceous glands do, which is why sebaceous glands are specifically identified as the structures that connect to hair follicles and produce oil for the skin.