What is the main role of sebaceous glands in the skin?

Sebaceous glands play a crucial role in maintaining the health of hair and skin primarily by secreting an oily substance known as sebum. This natural oil serves to lubricate the hair and skin, preventing them from becoming dry and brittle. Sebum also has protective properties, as it helps to form a barrier that can prevent the entry of harmful microorganisms and reduce the risk of skin infections. Additionally, by keeping the skin moisturized, sebaceous glands contribute to overall skin health and appearance.

While other functions such as temperature regulation and hydration are important aspects of skin function, they are typically managed by other structures, such as sweat glands and the skin's ability to retain moisture. The primary and most direct function attributed to sebaceous glands is indeed to lubricate and protect both hair and skin.