Certified Nephrology Nurse Exam Practice 2025 – Complete Study Guide

The vasa recta play a crucial role in the concentration of urine. These are specialized capillaries that run alongside the nephron loops (specifically the loops of Henle) in the renal medulla. Their primary function is to maintain the osmotic gradient established by the loop of Henle, which is essential for the kidney's ability to concentrate urine.

As blood flows through the vasa recta, it participates in the countercurrent exchange mechanism. This allows for the reabsorption of water and solutes as it descends and ascends through the medulla. The osmotic gradient created by the longer loop of Henle and maintained by the vasa recta enables the kidney to concentrate urine efficiently, which is vital for water conservation and proper fluid balance in the body.

In summary, the primary function of the vasa recta in the kidney is to facilitate the concentration of urine through their involvement in the countercurrent exchange system, supporting the kidney's ability to concentrate waste and conserve water.