There are two main types of circulation in our body. When the circulatory path for blood flows via lungs, it is Pulmonary Circulation. Whereas, the path that supplies oxygen to the body cells is systemic circulation. Heart pumps blood to the entire body. The pumping of blood happens due to the contraction of heart muscles. Coronary artery supplies blood to the heart muscles. The two valves namely superior vena cava and inferior vena cava is used for entry of blood into right artery. Inferior vena cava collects the blood from the body organs and the legs. However, the superior vena cava collects blood from head and hands. The blood circulated in the heart is collected with help of coronary sinus and sends them to right atrium. When the right atrium is filled with blood, the heart muscles start to contract. Due to this, blood flows into the right ventricle via tricuspid valve. When the pressure inside right ventricle becomes higher than the right atrial pressure, tricuspid valve is closed.
The other valve called semilunar valve is opened due to the pressure inside right ventricle. Now the blood flows to the lungs through pulmonary artery. Lungs are the organ, which provides purification of blood in our body. So now, when the blood reaches lungs, blood is oxygenated and given to left atrium via pulmonary veins. Here we have another valve named Mitral valve or Bicuspid valve. Once the left atrium is filled with pure blood, the mitral valve is opened. The blood is pumped to left ventricle. The valve is closed, when pressure is high in the left ventricle. During the cycle, left ventricle is filled with blood and opens the aortic valve. Through aortic valve blood is sent to body organs like hands, legs, head and coronary artery. Pumping action is divided into two parts as systole and diastole. The period of ventricle contraction is Systole. The time for the blood to fill the heart chamber is Diastole.