Click here to close.Click here to view disclaimer.
Share this page from the NHLBI on Blogger.
Share this page from the NHLBI on Buzz.
Share this page from the NHLBI on Delicious.
Share this page from the NHLBI on Digg.
Share this page from the NHLBI on Facebook.
Add this link to the NHLBI to my browser.
Email this page with Gmail.
Bookmark this page with Google.
Share this page from the NHLBI on LinkedIn.
Share this page from the NHLBI on Messenger.
Share this page from the NHLBI on MySpace.
Share this page from
the NHLBI on Reddit.
Share this page from the NHLBI on Stumble.
Share this page from the NHLBI on Tumblr.
Share this page from the NHLBI on Twitter.
How the Heart Works
To understand congenital heart defects, it's helpful to know how a healthy heart works. Your child's heart is a muscle about the size of his or her fist. The heart works like a pump and beats 100,000 times a day.
The heart has two sides, separated by an inner wall called the septum. The right side of the heart pumps blood to the lungs to pick up oxygen. The left side of the heart receives the oxygen-rich blood from the lungs and pumps it to the body.
The heart has four chambers and four valves and is connected to various blood vessels. Veins are blood vessels that carry blood from the body to the heart. Arteries are blood vessels that carry blood away from the heart to the body.
A Healthy Heart Cross-Section
The illustration shows a cross-section of a healthy heart and its inside structures. The blue arrow shows the direction in which oxygen-poor blood flows from the body to the lungs. The red arrow shows the direction in which oxygen-rich blood flows from the lungs to the rest of the body.
Heart Chambers
The heart has four chambers or "rooms."
The atria (AY-tree-uh) are the two upper chambers that collect blood as it flows into the heart.
The ventricles (VEN-trih-kuhls) are the two lower chambers that pump blood out of the heart to the lungs or other parts of the body.
Heart Valves
Four valves control the flow of blood from the atria to the ventricles and from the ventricles into the two large arteries connected to the heart.
The tricuspid (tri-CUSS-pid) valve is in the right side of the heart, between the right atrium and the right ventricle.
The pulmonary (PULL-mun-ary) valve is in the right side of the heart, between the right ventricle and the entrance to the pulmonary artery. This artery carries blood from the heart to the lungs.
The mitral (MI-trul) valve is in the left side of the heart, between the left atrium and the left ventricle.
The aortic (ay-OR-tik) valve is in the left side of the heart, between the left ventricle and the entrance to the aorta. This artery carries blood from the heart to the body.
Valves are like doors that open and close. They open to allow blood to flow through to the next chamber or to one of the arteries. Then they shut to keep blood from flowing backward.
When the heart's valves open and close, they make a "lub-DUB" sound that a doctor can hear using a stethoscope.
The first sound—the "lub"—is made by the mitral and tricuspid valves closing at the beginning of systole (SIS-toe-lee). Systole is when the ventricles contract, or squeeze, and pump blood out of the heart.
The second sound—the "DUB"—is made by the aortic and pulmonary valves closing at the beginning of diastole (di-AS-toe-lee). Diastole is when the ventricles relax and fill with blood pumped into them by the atria.
Arteries
The arteries are major blood vessels connected to your heart.
The pulmonary artery carries blood from the right side of the heart to the lungs to pick up a fresh supply of oxygen.
The aorta is the main artery that carries oxygen-rich blood from the left side of the heart to the body.
The coronary arteries are the other important arteries attached to the heart. They carry oxygen-rich blood from the aorta to the heart muscle, which must have its own blood supply to function.
Veins
The veins also are major blood vessels connected to your heart.
The pulmonary veins carry oxygen-rich blood from the lungs to the left side of the heart so it can be pumped to the body.
The superior and inferior vena cavae are large veins that carry oxygen-poor blood from the body back to the heart.
For more information about how a healthy heart works, go to the Health Topics How the Heart Works article. This article contains animations that show how your heart pumps blood and how your heart's electrical system works.
WAS THIS HELPFUL?
Your rating was 1 star(s)
Your rating was 2 star(s)
Your rating was 3 star(s)
Your rating was 4 star(s)
Congenital Heart Defects Clinical Trials
Clinical trials are research studies that explore whether a medical strategy, treatment, or device is safe and effective for humans. To find clinical trials that are currently underway for Congenital Heart Defects, visit www.clinicaltrials.gov.
Visit Children and Clinical Studies to hear experts, parents, and children talk about their experiences with clinical research
July 01, 2011
The NHLBI updates Health Topics articles on a biennial cycle based on a thorough review of research findings and new literature. The articles also are updated as needed if important new research is published. The date on each Health Topics article reflects when the content was originally posted or last revised.