The blood vessels that transport blood into and out of the kidneys arise from and merge with the aorta and inferior vena cava, respectively. The urine leaves the kidney through the ureter and is stored in the urinary bladder.

It is an equilibrium because body functions are kept within a normal range, with some fluctuations around a set point. The kidneys are the main osmoregulatory organs in mammalian systems; they function to filter blood and maintain the dissolved ion concentrations of body fluids.

kidneys — the main osmoregulatory organs in mammalian systems; they function to filter blood and maintain the dissolved ion concentrations of body fluids. inferior vena cava — the major vein of the body returning blood from the lower parts of the body to the right atrium. aorta — the major artery that takes blood away from the heart to the systemic circulatory system. equilibrium because body functions — kept within a normal range, with some fluctuations around a set point.