What defines glands in the human body?

In the context of the human body, glands are defined as specialized organs that have the primary function of producing and secreting substances essential for various bodily functions. This includes hormones, enzymes, mucus, and other fluids. Glands can be classified as endocrine or exocrine, depending on how they release their products. Endocrine glands, such as the thyroid and adrenal glands, release hormones directly into the bloodstream, while exocrine glands, like sweat and salivary glands, secrete substances through ducts to specific locations.

The role of specialized organs that remove and convert elements from the blood aligns with the broader function of glands, focusing on how they interact with bodily fluids and contribute to metabolic processes. This definition encompasses how glands process various substances, highlighting their essential role in maintaining homeostasis and overall bodily function.

While other options discuss structures and cells, they do not specifically capture the essence of what defines glands in terms of their function and contribution to the body's systems. Glands are not merely fluid-filled cavities or general groups of cells, but intricate structures pivotal in producing vital secretions and regulating physiological processes.