noun, plural: tubules
A small tube-like or fistular structure; a hollow cylindrical anatomical structure in the organs of the body
In anatomy, a tubule pertains to a small tube-like structure that is lined with glandular epithelium. There are many tubules found in various bodily organs. For instance, the collecting tubules are the terminal channels of the nephrons. Nephrons are the structural and functional unit of the kidney. It connects to the ureter vial a series of collecting tubules and ducts, which are collectively known as the collecting duct system. One particular tubule of the nephron is the distal convoluted tubule that is characterized by its convoluted portion and is found near the loop of Henle. The loop of Henle is also a tubule shaped like a horseshoe. Other particular renal tubules are the proximal and the distal convoluted tubules. The Malpighian tubule of certain insects is a tubule in the abdominal body cavity of the insect and is associated with excretion. Another tubule is the Cuvierian tubule, which is a sticky tubule at the base of the respiratory tree of the lung. Sea cucumbers are capable of discharging this tubule when threatened by a predator.