NBEO General Physiology Practice Exam 2025 – Complete Study Resource

Exocrine glands are characterized by their method of secretion, which involves releasing their products through ducts. These ducts facilitate the transport of the gland's secretions directly to specific target sites, such as the surface of an organ or the skin, rather than distributing them throughout the body via the bloodstream. This localization of secretion allows for precise regulation and immediate effects on the surrounding tissues.

In contrast, other gland types, such as endocrine glands, secrete their products directly into the bloodstream, enabling widespread effects throughout the body. Glands that secrete into interstitial fluid typically involve a different mechanism without ductal transport, and metabolic regulation is more closely associated with hormones from endocrine glands rather than the localized secretions of exocrine glands. Thus, the defining feature of exocrine glands is their ductal secretion pathway, making the response that emphasizes secretion through ducts the most accurate description.