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.
The heart is the hollow, muscular organ in the thoracic cavity (chest) that maintains the circulation of blood throughout the body. It is surrounded by a membrane called the pericardium.lood passes from the left atrium through the mitral valve and into the left ventricle. The left ventricle, the largest and most muscular of the four chambers, is the main pumping chamber of the heart.