What are collecting ducts and their histological features?
Collecting ducts are tubular structures that receive urine from the distal convoluted tubules and transport it through the medulla to the renal pelvis. Histologically, they are lined with a mix of principal cells, which regulate water and sodium reabsorption, and intercalated cells, which are involved in acid-base balance. The ducts become progressively larger and merge into papillary ducts that open into the renal pelvis.
