What is the main function of sebaceous glands?

The main function of sebaceous glands is to secrete oil, specifically a substance known as sebum. Sebum is vital for maintaining the health of the skin and hair as it provides moisture and acts as a natural barrier against external pollutants and microbes. This oily secretion helps to keep the skin hydrated, prevents dryness and flakiness, and contributes to the skin's overall elasticity.

Sebaceous glands are typically associated with hair follicles, and they are present throughout most of the body, except on the palms of the hands and soles of the feet. Their activity can be influenced by various factors, including hormones, which is why many individuals experience changes in oil production during puberty or in different seasons.

The other options relate to different physiological processes: sweat production is primarily the function of sweat glands, temperature regulation involves various body mechanisms including sweating and blood flow adjustments, and blood filtration is performed by the kidneys. Understanding the specific role of sebaceous glands highlights their importance in skin health and overall body function.