What is the function of the collecting ducts in the urinary system?

The collecting ducts play a crucial role in the final stages of urine formation within the urinary system. Their primary function is to transport urine from the nephrons to the renal pelvis, where it will then flow into the ureters and eventually to the bladder. This process is a vital part of maintaining the body's fluid balance and involves transporting processed filtrate that has already been adjusted for excess water and solutes.

While the collecting ducts can influence the concentration of urine through reabsorption and secretion, their main physiological role is to effectively channel the urine produced by the nephrons, which includes collecting and concentrating urine before it reaches the renal pelvis. This function is essential for the proper functioning of the urinary system and maintaining homeostasis within the body.

Other options present functions that are not performed by the collecting ducts. For instance, filtering blood for excess substances is primarily done by the glomeruli in the nephrons. Producing hormones regulating hydration is typically associated with organs like the kidneys and glands like the adrenal glands. Storing urine until expelled is a function of the bladder, which serves as the reservoir for urine before it is excreted from the body.