Which glands produce an oily substance called sebum?

Sebaceous glands are specialized structures in the skin that produce an oily substance known as sebum. This secretion is important for maintaining the health of the skin and hair, as sebum helps to lubricate and protect these surfaces from becoming dry and damaged. The presence of sebum also plays a role in the skin's ability to provide a barrier against certain pathogens.

The production of sebum begins at puberty, influenced by hormonal changes, particularly the increase of androgens. This is why teenagers often experience more oily skin and acne: the sebaceous glands become more active during this time.

The other glands listed do not produce sebum. Salivary glands secrete saliva, which aids in digestion and oral health. Pituitary glands are endocrine glands that produce various hormones regulating numerous body functions, including growth and metabolism. Endocrine glands refer to a broad category of glands that secrete hormones directly into the bloodstream, but they do not produce sebum specifically. Thus, sebaceous glands are uniquely responsible for sebum production.