DNA replication is the process by which a double-stranded DNA molecule is copied to produce two identical DNA molecules.
The heart pumps oxygenated blood to the body and deoxygenated blood to the lungs. In the human heart there is one atrium and one ventricle for each circulation, and with both a systemic and a pulmonary circulation there are four chambers in total: left atrium, left ventricle, right atrium and right ventricle.
systemic circulation. The blood flow from the left ventricle through the aorta and all its arteries to the capillaries of the tissues and its return to the heart through veins and the venae cavae, which empty into the right atrium. See: illustration. See also: circulation.