The Cardiovascular System – Heart Valves

By: Alere Staff

The human heart is made up of four chambers: two upper chambers known as the atria and two lower chambers known as the ventricles. These chambers are separated by valves which are flap-like structures that allow blood to flow in only one direction. Valves prevent blood from flowing backward as it leaves each chamber of the heart.

While there are four valves controlling blood flow through the heart, there are two different types of valves. The atrioventricular valves are those that are positioned between the atria and ventricles. These are the mitral valve on the left side of the heart and the tricuspid valve on the right side of the heart.

The other type of valve is the semilunar valve. There are two of these as well and they control the flow of blood as it leaves each ventricle. The pulmonic valve is situated between the right ventricle and the pulmonary artery and the aortic valve is between the left ventricle and the aorta.

As the heart muscle contracts and relaxes in its relentless pumping, the valves open and close to allow blood to fill and empty the chambers. This opening and closing of valves is what creates the “lub-dub” sounds of the human heart at work.

Disease or malfunctioning of heart valves can create very serious physical conditions. When valves are unable to fully close, blood leakage or “regurgitation” backward can cause strain on the heart.

Valve stenosis is a condition where the valve is unable to fully open due to a narrowing or stiffness of the valve. In this situation, the heart has to work harder to pump blood through this restricted passage. Failure of heart valves to open or close properly can have potentially life-threatening consequences if they are not surgically repaired or replaced. It is essential to pay attention to the health of the heart to assure it is adequately able to keep blood pumping through the body.

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  1. Anatomy and Function of the Heart Valves. The Johns Hopkins University Health Library. Retrieved April 16, 2015 from the website:,P03059/.
  2. Bailey, R. Anatomy of the Heart: Valves. About Education. Retrieved April 16, 2015 from website: