What do 'sebaceous glands' produce?

Sebaceous glands are specialized glands located in the skin that are responsible for producing an oily substance known as sebum. This secretion plays a crucial role in maintaining the health of the skin and hair by providing moisture and protecting against bacteria and environmental damage. Sebum helps to keep the skin lubricated and prevents it from becoming dry and brittle, which can lead to various skin conditions. The production of sebum is influenced by several factors, including hormonal changes, which is why during puberty, for example, sebaceous glands are particularly active.

The other choices pertain to different bodily functions. Hormones regulating metabolism are produced by endocrine glands, not sebaceous glands. Saliva, needed for digestion, is produced by salivary glands, while fluid that lubricates joints is secreted by synovial membranes in the joints. Therefore, the focus on oily secretion aligns specifically with the function of sebaceous glands, confirming that the correct response is indeed the production of sebum.