What do atria and ventricles do

Stenosis is a narrowed valve. With stenosis, the valve opening is narrowed and the valve doesn't open correctly. This makes it harder for the heart to pump blood across the narrowed valve. The heart must use more force to pump blood through the stiff stenotic valve or valves. This can also cause structural and functional changes to the different chambers of the heart.

These changes prevent the heart from pumping blood normally. This means the valve opening doesn't develop normally during childhood. This prevents blood from passing from an atria to a ventricle, or from a ventricle to the pulmonary artery or aorta. Blood must find another route. This is usually through a problem present at birth congenital.

This might be an atrial septal defect or a ventricular septal defect. This acts as another route for the blood to move through the heart. When heart valves fail to open and close correctly, the damage to the heart can be serious. The harm can affect the heart's ability to pump blood through the body. Search Encyclopedia.

Your heart has its own electrical system that coordinates the work of the heart chambers heart rhythm and also controls the frequency of beats heart rate.

The task of your heart is to pump enough blood to deliver a continuous supply of oxygen and other nutrients to the brain and the other vital organs. To do this, your heart needs to:. Author: Healthwise Staff.

Medical Review: Rakesh K. This information does not replace the advice of a doctor. Healthwise, Incorporated, disclaims any warranty or liability for your use of this information. Your use of this information means that you agree to the Terms of Use. Learn how we develop our content. To learn more about Healthwise, visit Healthwise. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated. Updated visitor guidelines.

You are here Home » How the Heart Works. Top of the page. Topic Overview The heart is at the center of your circulatory system, which is a network of blood vessels that delivers blood to every part of your body. Your heart is a muscle, and its job is to pump blood throughout your circulatory system.

At each body part, a network of tiny blood vessels called capillaries connects the very small artery branches to very small veins. The capillaries have very thin walls, and through them, nutrients and oxygen are delivered to the cells. Waste products are brought into the capillaries. Capillaries then lead into small veins. Small veins lead to larger and larger veins as the blood approaches the heart. Valves in the veins keep blood flowing in the correct direction. Two large veins that lead into the heart are the superior vena cava and inferior vena cava.

The terms superior and inferior don't mean that one vein is better than the other, but that they're located above and below the heart. Once the blood is back in the heart, it needs to re-enter the pulmonary circulation and go back to the lungs to drop off the carbon dioxide and pick up more oxygen.

How Does the Heart Beat? This is when the ventricles contract and pump blood into the aorta and pulmonary artery. During systole, the atrioventricular valves close, creating the first sound the lub of a heartbeat. When the atrioventricular valves close, it keeps the blood from going back up into the atria. During this time, the aortic and pulmonary valves are open to allow blood into the aorta and pulmonary artery.

When the ventricles finish contracting, the aortic and pulmonary valves close to prevent blood from flowing back into the ventricles. These valves closing is what creates the second sound the dub of a heartbeat. The second phase is called diastole die-AS-tuh-lee.

This is when the atrioventricular valves open and the ventricles relax. The left atrium receives the now oxygen-rich blood from the lungs and pumps it into the left ventricle.

The left ventricle pumps the oxygen-rich blood to the body through a large network of arteries. The contractions of the left ventricle, the strongest of the four chambers, are what create blood pressure in the body. A series of four valves open and close to allow blood to move through the heart. The tricuspid valve that controls blood flow from the right atrium to the right ventricle. The pulmonary valve that regulates blood flow from the right ventricle to the pulmonary arteries.