The excretory system consists of the kidneys, ureters, urinary bladder, and urethra, and is essential for removing waste from the body. The kidneys filter blood to remove waste and regulate salt levels, producing urine that passes through the ureters into the bladder. The bladder stores urine until it is expelled through the urethra. Other excretory organs include the skin, which sweats out salt and water, the large intestine and lungs, which remove waste, and the liver, which produces bile to remove waste from the blood.