Final answer:
Sebaceous glands are holocrine glands that rupture to release sebum, an oily substance to protect and moisturize the skin and hair. New cells replace the destroyed ones.
Step-by-step explanation:
The sebaceous glands are a type of holocrine gland, which is characterized by the way it releases its secretory products. In holocrine secretion, the gland cells accumulate their product and then the entire cell ruptures, thus releasing the collected secretion. After the cell bursts, it is destroyed, and its contents are released to lubricate the skin and hair. New glandular cells are then differentiated from surrounding tissue cells to take the place of those that have been lost. Sebaceous glands are responsible for producing sebum, the oily substance that maintains the moisture and protects the skin and hair while also exhibiting antibacterial properties.