The loop of Henle is a U-shaped section of the nephron, which is the functional unit of the kidney. It plays a crucial role in concentrating urine and maintaining the body's water balance. As urine passes through this loop, water is reabsorbed in the descending limb, while salts are reabsorbed in the ascending limb, creating a concentration gradient that helps the kidneys manage hydration levels. This structure is named after the German anatomist Friedrich Gustav Jakob Henle, who first described it in the 19th century. The loop of Henle is essential for the body's ability to conserve water, especially in dry environments, ensuring that we stay hydrated and our blood pressure remains stable.