Fill in the blanks below with the correct answers. Kidneys are the filters of the system. They control the essential balance between body salts and remove nitrogenous wastes, water, urea, nonvolatile foreign substances, excess salt, and excess water from the blood. The kidney is enclosed by connective tissue and is divided into an outer and an inner region. The outer region functions chiefly for water resorption. The liquid waste, urine, collected by the kidneys passes through the ureters to the urinary bladder. The urinary bladder is a strong muscular organ that stores the urine until it can be excreted via the urethra.