Circulatory system is a system consisting of extracellular fluid (including plasma, lymph and interstitial fluid) and the pipes that they circulates via. After the formation of creaturely heart, circulatory system is divided into two parts, heart and blood vessels, called the cardiovascular system. Circulatory system is the transportation system in organism. It transports nutrients assimilated by the digestive tract and oxygen inhaled by lungs or gills to various tissues and organs, and conveys the metabolites from various tissues and organs into the blood and then into pulmonary and renal excretion through the same paths. It also transports heat to parts all around the body to maintain body temperature as well as hormone to target organs in order to regulate their function.
Circulatory system drugs includes anti-anginal drugs, anti-arrhythmic drugs, anti-hypertensive drugs, anti-shock vasoactive drugs, lipid regulating drugs and anti-atherosclerotic agents, peripheral vasodilation agents, calcium antagonists, anti-heart-failure drugs and drugs for the treatment of chronic cardiac insufficiency.