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 human heart is an organ that pumps blood throughout the body via the circulatory system, supplying oxygen and nutrients to the tissues and removing carbon dioxide and other wastes.eoxygenated blood returns via veins to the venae cavae, re-entering the heart's right atrium. Of course, the heart is also a muscle, so it needs a fresh supply of oxygen and nutrients, too, Phillips said. The cardiovascular system circulates blood from the heart to the lungs and around the body via blood vessels.