When do valves open and close

When the heart valves open and close, they create sounds we know as our heartbeat. Here is an overview of circulation through the heart: First, blood returns from the body to the right atrium. This blood has been depleted of oxygen when the oxygen was delivered to the body tissues, so it is seeking more oxygen to keep the process going. The right atrium, now full of oxygen-depleted blood, pumps the blood through the tricuspid valve into the right ventricle.

Then the right ventricle contracts to pump blood through the pulmonary valve into the pulmonary artery. The pulmonary artery brings blood away from the heart to the lungs where the blood receives the oxygen we breathe, becoming oxygen-rich blood. At the same time the above process is occurring, oxygen-rich blood is returning from the lungs by way of the left atrium.

The left atrium then moves the blood through the mitral valve into the left ventricle. Name required. E-Mail Address will not be published required. Submit Comment. Janelle says, "I finally had my first surgical consult Lisa says, "Has anyone had pain at top of sternum Search Heart Hospitals Search Hospitals. Janelle Hurst from Jacksonville, FL says. I finally had my first surgical consult! Felt good to actually. The four heart valves open and close in response to pressure changes that occur in the ventricles during each cardiac cycle.

When the ventricles relax, their pressures drop below those of the atria, pulmonary trunk artery, and aorta. This allows the AV valves to open as their cusps passively drop downward. The pressure change additionally permits blood flow into the ventricles from the atria without restriction.

The semilunar valves close during this same period as blood flowing toward the ventricles collects in the pockets of the cusps. When the ventricles contract, the tricuspid and mitral valve are forced shut while the ventricular outflow valves, the pulmonic and the aortic valves, are forced open by the ventricular pressure. Blood leaving the ventricles is prevented from flowing backwards by the tight seal formed by the cusps of the aortic and pulmonic valves.

There are several disorders that can affect valve function, including valvular regurgitation and valvular stenosis. Common Health Topics.