There are four heart chambers, the right atrium, left atrium, right ventricle and left ventricle. These receive blood from the body and lungs and contract to transmit blood to the lungs for oxygenation and to the body for use in metabolism.
It is best to list the four chambers in order of the series that blood travels through the heart:
venous blood returning from the body drains into the right atrium via the SVC, IVC and coronary sinus
the right atrium pumps blood through the tricuspid valve into the right ventricle
the right ventricle pumps blood through the pulmonary semilunar valve into the pulmonary trunk to be oxygenated in the lungs
blood returning from the lungs drains into the left atrium via the four pulmonary veins
the left atrium pumps blood through the bicuspid (mitral) valve into the left ventricle
the left ventricle pumps blood through the aortic semilunar valve into the ascending aorta to supply the body
