glandulae

Glandulae, or glands, are specialized organs that produce and secrete substances for local, digestive, or systemic use. In anatomy, glands are classified by the route of their secretions: exocrine glands release products through ducts to surfaces or body cavities, while endocrine glands release hormones directly into the circulatory system. Some glands are mixed, containing both secretory units and ductal structures.

Structurally, secretory units may be arranged as acini or tubules; combinations yield tubuloalveolar or tubuloacinar glands. Secretions can be serous, mucous, or mixed. Glandular secretion can occur by merocrine, apocrine, or holocrine mechanisms, reflecting the fate of the secretory cells.

Representative exocrine glands include the salivary glands, lacrimal glands, sweat glands, sebaceous glands, and the exocrine pancreas. Endocrine glands include the pituitary, thyroid, parathyroid, and adrenal glands; the islets of Langerhans in the pancreas form the endocrine portion; and the gonads likewise function as endocrine organs. Many organs contain both exocrine and endocrine components.

Developmentally, glandular tissue arises from epithelial lining and often invaginates to form ducts, with subsequent vascularization supporting secretion and transport of products to their targets.

Clinically relevant glandular disorders include hyperplasia, benign adenomas, and malignant adenocarcinomas; ductal obstruction and inflammatory diseases such as Sjögren’s syndrome; and dysregulation of endocrine glands leading to hormonal imbalances. The term glandulae reflects the Latin plural of glandula, used in anatomical nomenclature.