Tubuluses

Tubulus is a Latin-derived anatomical term referring to a small tube or duct. In modern English scientific usage, tubulus is usually treated as the singular form, with tubuli as the standard plural. Tubuluses is also encountered as an anglicized plural in some older or less formal texts. The term is used across multiple organ systems to denote any small tubular channel lined by epithelium, often involved in transport, secretion, or absorption.

Common examples appear in several contexts. In the kidney, renal tubules constitute segments such as the proximal tubule and distal tubule, which modify the filtrate produced by the glomerulus. In the testes, the seminiferous tubules (tubuli seminiferi) contain developing sperm and connect to the rete testis. In invertebrates, Malpighian tubules function in excretion and osmoregulation. Histologically, tubuli can be simple or branched, and their epithelial lining and supporting tissues vary with function. In the kidney, proximal tubules typically have a brush border of microvilli and abundant mitochondria, supporting active reabsorption, while distal tubules have a different epithelial profile suited to electrolyte balance. Tubuli may be embedded in connective tissue or form ducts within glands, and many are continuous with larger ducts or cavities. The term thus serves as a generic descriptor for numerous small tubular structures in anatomy.