double circulation the path in which the blood flows is called a circuit there are two circuits for flow of blood one pulmonary circuit between heart and lungs two systemic circuit between heart and organs of body a heart that pumps blood into two circuits is called double circuit heart pulmonary circuit or circulation in this circuit deoxygenated blood from right orle and then sent into right ventricle from right ventricle blood is pumped to the lungs in the lungs the blood is oxygenated and the oxygenated blood is returned to the left Oracle by pulmonary veins and then sent into left ventricle systemic circuit or circulation in this circuit oxygenated blood from left ventricle into the systemic aota this aota supplies blood to various organs in the body the deoxygenated blood from various organs is collected into inferior and superior vena cavi and finally into the right Oracle the systemic circulation provides nutrients O2 and other essential substances to the tissues and take CO2 and other harmful substances away from elimination a unique vascular connection exists between digestive tract and liver called hepatic portal system the hepatic portal vein carries blood from intestine to the liver before it is delivered to the systemic circulation a special coronary system of blood vessels is present in our body for circulation of blood to and from the cardiac musculature