Heart attack

The human heart is made up of cardiac muscle and its job is to pump blood throughout the body. It works constantly throughout its lifetime and, unlike other muscles in the body, it never tires. The heart is made up of four hollow chambers, the left atrium and right atrium, which receive blood, and the left ventricle and right ventricle, which pump the blood out of the heart. The heart muscle requires more oxygen than any other organ in the body (except the brain), but the blood that flows through the heart does not provide it with oxygen. The heart has its own blood supply, provided by ...