The major structural features of the human heart are its four chambers for pumping blood. The heart is commonly viewed as having a left side and a right side, with each side comprising two chambers -- an atrium and a ventricle. The four total chambers make up the organ's primary structural features. Together, they are responsible for maintaining blood flow throughout the body via the circulatory system. The heart is also responsible for moving waste products through the bloodstream to the organs that process them.