You know how important your heart is, so it's no wonder people worry when they hear someone has heart problems. More than 60 million Americans suffer from some form of heart disease. The heart is an extraordinary organ. Its job is to pump blood rich in oxygen and nutrients throughout the body to support life. In fact, this fist-sized organ beats, or expands and contracts, 100,000 times a day. It pumps five to six liters of blood per minute, or about 2,000 liters per day. That's a lot of blood. Blood is essential. It carries fresh oxygen from the lungs and nutrients to the body's tissues. It also moves the body's waste products, such as carbon dioxide, away from the tissues. (“How the Heart Works”) The heart is a hollow, four-chambered organ about the size of a fist. The atria make up the two upper chambers. They receive blood from the veins. The ventricles make up the two lower chambers. These chambers pump blood into the arteries. The heart is the center of the cardiovascular system. (“How the Heart Works”) Heart disease, also known as cardiovascular disease, is a group of problems that occur when the heart and blood vessels do not work as they should. When the coronary arteries narrow, blood has difficulty reaching the heart. This causes pain in the heart muscle, like any other muscle in the body. If the limbs continue to shrink, the heart is put under stress which causes symptoms of heart disease. Heart disease is not contagious. You can't take it from someone else. There are many factors that increase a person's chances of developing heart disease. People do not have control over some of these factors, such as aging or having family members who have had the same problems. But they have control over some of these fa… middle of paper… Centers for Disease Control and Prevention. Centers for Disease Control and Prevention, May 9, 2013. Web. May 3, 2014. "Risk Factors for Heart Disease and Stroke." WebMD. WebMD, Jan. 3, 2013. Web. May 3, 2014."Facts about heart disease." Centers for Disease Control and Prevention. Centers for Disease Control and Prevention, February 19, 2014. Web. May 3, 2014.Wedro, Benjamin, MD, Daniel Lee Kulick, MD, and Melissa Conrad Stoppler, MD. “Heart Disease (Coronary Artery Disease): Read the Symptoms.” MedicineNet. Np, nd Web. May 03, 2014."10 Risk Factors for Heart Disease." Your risk of high cholesterol |. Np, nd Web. May 03, 2014."How the heart works." WebMD. WebMD, Jan. 29, 2013. Web. May 2, 2014."Heart Disease." KidsHealth: The most visited children's health site on the web. Ed. Steven Dowshen. The Nemours Foundation, 01 June 2013. Web. 03 May 2014.