The heart is the organ that pumps blood throughout the body. It has three chambers: the atria, the ventricles and the septum. It also contains two main valves: the tricuspid and the premolar (the atrioventricular valves). It has two sections that carry the different types of blood (oxygenated and deoxygenated). Oxygen-depleted blood passes through the right atrium to the right ventricle. From the right ventricle, blood exits the pulmonary artery to the lungs; which are called pulmonary circuits. Oxygen-rich blood travels from the lungs to the left ventricle. From the left atrium it travels towards the left ventricle and through the aorta it reaches the different parts of the body; called systemic