Which system helps maintain water and electrolyte balance in the body?

The urinary system plays a crucial role in maintaining the body's water and electrolyte balance. It primarily involves the kidneys, which filter blood to create urine, allowing for the excretion of waste products while regulating the balance of water and essential electrolytes such as sodium, potassium, and calcium. By adjusting the amount of water and ions that are reabsorbed or excreted, the urinary system helps to ensure that the body does not become dehydrated or overloaded with excess substances. This delicate balance is essential for various physiological functions, including muscle contraction, nerve function, and maintaining blood pressure, making the urinary system vital for homeostasis.

The other systems mentioned do not primarily focus on water and electrolyte balance. The nervous system is more involved in signal transmission and reflex actions, the muscular system is responsible for movement, and the circulatory system mainly transports nutrients, gases, and hormones throughout the body rather than directly regulating water and electrolyte levels.