Collecting ducts of the kidney (400X)

Collecting ducts from multiple nephrons merge in the medulla, and they are responsible for the final concentration or dilution of urine based on the body's hydration status. The hormone contolling this process is called antidiuretic hormone (ADH) and comes from the neurohypophysis. ADH increases the reabsorption of water in the distal tubules and in the collecting ducts so that the body's water loss is reduced.

The epithelium varies depending on wich part of the loop of Henle you look at. In the thin part there is squamous epithelium, while in the thick part cubical epithelium is found. It ie easy to spot the difference in this image. try for yourself.

The collecting ducts manly consist of cubic to cylindrical epithelium. They have a lighter color than thick parts of Henle's loop, lack microvilli and have a clear border between the cells.