Through a series of intricate pathways, capillaries and tunnels, the vasa recta help the kidney produce concentrated urine. The vasa recta contain a group of capillaries and vessels located in the kidneys. Biologically, the vasa recta lay parallel to the loop of Henle, which facilitates the flow of blood into and out of the kidneys.
Each vasa recta in the kidneys has a small turn in the medulla that transports blood away at a slow rate. This regulation of blood is important for maintaining a countercurrent exchange between the vasa recta and the loop of Henle; these two components work together to process and filter blood to remove impurities before sending it elsewhere in the urinary system and throughout the body. The ability of the vasa recta to regulate blood is critical. This task is what triggers the kidneys to produce and excrete concentrated urine. According to the North Carolina Wesleyan College, the vasa recta, in addition to having a series of short and straight capillaries, contain a long, descending tube on the downward side. In this tunnel, calcium and urea are cleansed and reabsorbed into the bloodstream. In the process, water is produced and secreted from the walls of the vasa recta. That water, like blood, is cleansed and exported throughout the body.