How and why the volume and composition of urine changes after drinking a lot of water?

When you drink a lot of water, the volume of urine increases due to the kidneys filtering excess fluid from the bloodstream to maintain homeostasis and regulate hydration levels. The composition of urine also changes, becoming more diluted with lower concentrations of solutes such as urea and electrolytes, as the body excretes the surplus water. This process helps prevent overhydration and ensures that the body's electrolyte balance remains stable.