What is the main function of sebaceous glands?

The main function of sebaceous glands is to produce sebum, an oily substance that plays a crucial role in maintaining the health of the skin and hair. Sebum acts as a natural moisturizer, providing lubrication that keeps the skin soft and prevents it from becoming dry and flaky. Additionally, sebum has waterproofing properties that help to protect the skin from external elements, including bacteria and excess moisture. This protective function contributes to the barrier role of the skin, making it less permeable to harmful substances and helping to maintain overall skin integrity.

In contrast, producing melanin is the primary function of melanocytes, which are responsible for skin pigmentation and provide some protection against UV radiation. Sensing temperature changes is the role of various sensory receptors in the skin, while regulating blood flow is primarily accomplished by the vascular system, particularly through adjustments in the diameter of blood vessels. Therefore, the specific role of sebaceous glands in producing sebum makes this option the correct answer.