What role do the kidneys play in the body?

The kidneys are vital organs in the body primarily responsible for filtering blood and producing urine. Their main function is to remove waste products and excess substances from the bloodstream, which includes toxins, urea, and other metabolites. By filtering blood through millions of tiny functional units called nephrons, the kidneys help maintain the body's fluid and electrolyte balance. This process also regulates the volume and pressure of blood, which is essential for overall homeostasis.

In addition to waste filtration, the kidneys play a role in regulating blood pH and electrolytes, as well as influencing blood pressure through the renin-angiotensin-aldosterone system. The urine produced is composed of these filtered wastes, excess water, and electrolytes, which are then excreted from the body, playing a crucial part in the body's waste management system. Thus, understanding the function of the kidneys is critical in understanding how the body maintains internal balance and health.