How blood circulates through the body?

Let's start with deoxygenated blood at the heart. It enters the right atrium of the heart, then passes into the right ventricle. From here, it is pumped to the lungs where gaseous exchange takes place. After this, it returns to heart, the left atrium this time. It passes into the left ventricle and is pumped to all the other organs in the body. The deoxygenated blood returns to the heart to complete the circuit.