Heart is the wondrous pump that powers the human body. With each heartbeat, it sends life-giving blood throughout the body. Blood carries oxygen and food to all the body cells. The rhythmic beating of the heart begins about seven months before we are born. When the heart stops beating, we die unless a special device circulates and oxygenates our blood.

    The heart is a large, hollow, muscular organ divided into two pumps that lie side by side. Veins transport blood from throughout the body to the right-sided pump. That pump sends the blood to the lungs, where it picks up oxygen. The oxygenated blood then flows to the left side of the heart, which pumps it through arteries to the rest of the body. Valves control the flow of blood through the heart. The left-sided pump, which delivers blood throughout the body, is larger and stronger than the right pump.

    The nervous system regulates the heart and other parts of the circulatory system. A division of the nervous system, the autonomic nervous system, automatically controls the heart rate, increasing or decreasing it, depending on the body's needs. For example, the heart pumps slowly while a person sleeps, providing relatively small amounts of oxygen to the body. But the heart rate can be quickly speeded up and so increase the oxygen output enormously when a person exercises, becomes frightened, or needs to fight or run.

    Disease can strike any part of the heart. Disorders of the heart and blood vessels are the leading cause of death in the United States and many other countries. The most common heart disease affects the arteries that supply the heart muscle itself with blood. Disorders of those arteries usually develop over a person's lifetime. Deposits of fatty material block the arteries and so reduce the blood supply to the heart. If the heart muscle receives too little blood, it may work poorly or even die. Damage to the heart muscle resulting from a shortage of blood is called a heart attack. A mild heart attack may force a person to lead a less active life. A severe attack may make the heart unable to supply the body with enough blood even at rest and so cause a person's death. Disease may also strike other parts of the heart with equally destructive effects.

    Some of the most exciting advances in medicine have been in cardiology, the medical field that deals with diseases of the heart and blood vessels. For thousands of years, people with heart diseases did not even know they had such a problem. In the 1900's, doctors have learned to diagnose and treat certain heart conditions that once meant death. Discoveries of new drugs and the great progress in surgery have added years to the lives of many heart patients. Doctors have transplanted hearts and even developed machines that can temporarily do the work of the heart.

    Today, much research in cardiology focuses on learning about the causes of heart disease so that it can be prevented. Other research seeks to reduce death and disability from heart disease through the further development of new medicines and surgical techniques. For patients who have untreatable disorders, research continues into improving heart transplantation and producing an effective artificial heart.

    Interesting Facts About The Heart

• The Human Heart is fully developed about eight weeks after
  conception, when the embryo is only about 1 inch (2.5 centimeters) long. The heart begins to beat even earlier--four weeks after conception, when it is just a simple tube.
  
• Ancient Egyptians believed that the heart was the center of the
  emotions and the intellect. An illustration from the ancient
  Egyptian Book of the Dead shows the god Anubis weighing a dead person's heart against a feather, the symbol of truth.