Manifold

Fine structure of the kidney, schematic.

A collecting tube ( Latin: tubulus renalis colligens ; also collecting tubule ) is a fine tube in the kidney for the drainage of urine from the nephrons . The collecting tubes run from the renal cortex ( Cortex renis ) through the renal medulla ( Medulla renis , Medulla renalis ) and open into the renal papillary duct ( Ductus papillaris ) and this in turn via a renal calyx into the renal pelvis .

About ten distal nephron sections open into a collecting tube. Several of these header pipes combine to form larger pipes. These in turn join together to form bundles. These bundles are called large collecting ducts (ductus papillares). These ductus papillares open into the kidney calyx at the renal papillae .

Historically, the collecting tubes arise from the ureteral bud .

The epithelial cells of the collecting ducts contain few cell organelles , which is why they appear light in routine histological specimens. The cell boundaries are clear, the epithelial height and the number of cell layers increase with the size of the tubes. The epithelium is usually not very permeable (permeable) for water. The antidiuretic hormone (vasopressin) ensures that this permeability is increased through the incorporation of aquaporins (AQP2) into the plasma membrane, whereby H ₂ O enters the hypertonic kidney medulla. This makes the urine more concentrated. Here a passive transport ( osmosis ) takes place due to the concentration gradient of the H ₂ O from the tubule to the renal medulla.

The collecting tube is also called Ductus Bellini or Tubulus Bellini after Lorenzo Bellini ; these tubules form the urinary ducts. Bellini duct carcinoma, a rare form of renal cell carcinoma, can develop in the collecting tube (medullary collecting tubule in the medulla renalis) .

Individual evidence

1. ↑ Günter Thiele (Ed.): Handlexikon der Medizin , Urban & Schwarzenberg , Munich, Vienna, Baltimore no year, Volume 4, S – Z, p. 2145.
2. ^ Maxim Zetkin , Herbert Schaldach: Lexikon der Medizin , 16th edition, Ullstein Medical, Wiesbaden 1999, ISBN 978-3-86126-126-X , p. 1777.
3. ^ Lexicon Medicine , 4th edition, Verlag Naumann & Göbel, Cologne no year [2005], ISBN 3-625-10768-6 , p. 1483.
4. ^ Jan Langman: Medical Embryology , 5th edition, Thieme-Verlag , Stuttgart 1977, ISBN 3-13-446605-8 , p. 122.
5. ↑ Ludwig August Kraus: Critical-etymological medical dictionary , 3rd edition, Deuerlich- and Dieterichsche Buchhandlung , Göttingen 1844, p. 1067.