Anterior (frontal) view of the opened heart. White arrows indicate normal blood flow.

Like the kidneys, the blood volume passes through the heart hundreds of time in a day. If blood pressure is too high, the heart releases atrionatriuretic factor (ANF). ANF is antagonistic to ADH. While ADH causes water retention by the collecting duct, ANF increases the excretion of sodium and water in copious urine.