What is the main role of the kidneys besides waste removal?

The primary role of the kidneys, in addition to waste removal, is to regulate fluid balance in the body. This function is vital for maintaining homeostasis, which is the stable and balanced internal environment necessary for optimal body function. The kidneys help control the amount of water and electrolytes in the body by filtering blood, reabsorbing what is needed, and excreting the excess through urine.

By adjusting the volume of fluid reabsorbed during the filtration process, the kidneys can influence blood pressure and overall fluid levels. This regulation assists in various bodily functions, including blood pressure control, electrolyte balance, and proper hydration. The kidneys effectively respond to changes in the body's needs, making them crucial for maintaining fluid balance.