tubulen

Tubulen is a term used in anatomy and histology to denote small tubular structures found throughout biology. In some languages, tubulen serves as the plural form of tubulus, a Latin-derived word meaning a small tube. The term is not a specific organ or molecule but a descriptive label for tissues, organs, or secretory units that have a tube-like shape and a luminal space.

In animals, many organs are organized around tubules. Renal tubules form the functional units of the kidney and include segments such as the proximal tubule, loop of Henle, distal tubule, and collecting duct, where fluids are filtered, reabsorbed, and concentrated. Seminiferous tubules in the testes are coiled structures that produce sperm. Many glands contain tubular secretory units, where secretions pass through a lumen. Tubulen are typically lined by epithelium and surrounded by supportive tissue; the epithelial cell type and degree of branching influence their transport, absorption, or secretion functions.

In plants, tubular structures occur in various tissues as elongated transport or secretory channels, contributing to internal movement of substances or localized secretion. In medicine and veterinary contexts, tubulopathy and tubular atrophy describe conditions in which the tubulen of organs such as the kidney are impaired, underscoring their essential roles in organ function.

See also tubulus, tubulin, and tubule.