Which glands are classified as exocrine glands?

Exocrine glands are specifically defined by their ability to secrete substances through ducts to the outside of the body or into body cavities. Sweat and salivary glands exemplify this function, as they both produce and transport their secretions—sweat and saliva, respectively—through ducts to the skin surface and oral cavity. This direct route for their secretions differentiates them from endocrine glands, which release hormones directly into the bloodstream without ducts.

In contrast, the other options involve glands that either do not have a duct system or primarily function in hormone production, which classifies them as endocrine glands. The thyroid and pituitary glands are known for their hormone secretions into the bloodstream; the adrenal glands primarily release hormones such as adrenaline and cortisol; and the thymus and pineal glands are also involved in endocrine functions and do not secrete substances through ducts. Thus, sweat and salivary glands clearly stand out as the quintessential examples of exocrine glands due to their duct-associated secretion process.