The excretory system is responsible for removing waste products and excess substances from the body, helping to maintain homeostasis. It primarily involves the kidneys, which filter blood to produce urine, eliminating toxins, salts, and water. This process regulates fluid balance, electrolyte levels, and blood pressure, while also playing a key role in acid-base balance. Overall, the excretory system is essential for keeping the body's internal environment stable and healthy.