The juxtaglomerular apparatus secretes renin when blood pressure is insufficient to drive filtration. I. This is later converted to angiotension II, which stimulates the adrenal cortex to release aldosterone. Aldosterone promotes sodium reabsorption, increasing blood volume and pressure. The heart secretes atrial natriuretic hormone when blood volume is too high. This inhibits the release of renin, and thus aldosterone.
Diuretics increase urine output, decreasing blood volume and pressure.
During respiration, the lungs remove CO2 from the blood. The sweat glands perspire, giving off salt, urea, and water. During kidney failure, sweat glands give off more urea. Bile pigments form during the breakdown of hemoglobin. Glomerular damage can lead to blocked glomeruli, or the glomeruli can become too permeable, allowing blood cells to be passed in the urine.