Anatomy and Function of the Heart Valves

Aorta
Aorta: The aorta is the largest single blood vessel in the body. It is approximately the diameter of your thumb. This vessel carries oxygen-rich blood from the left ventricle to the various parts of the body.
Pulmonary Valve
Pulmonary Valve: The pulmonary valve separates the right ventricle from the pulmonary artery. As the ventricles contract, it opens to allow the de-oxygenated blood collected in the right ventricle to flow to the lungs. It closes as the ventricles relax, preventing blood from returning to the heart.
Tricuspid Valve
Tricuspid Valve: The tricuspid valve separates the right atrium from the right ventricle. It opens to allow the de-oxygenated blood collected in the right atrium to flow into the right ventricle. It closes as the right ventricle contracts, preventing blood from returning to the right atrium; thereby, forcing it to exit through the pulmonary valve into the pulmonary artery
Right Atrium
Right Atrium: The right atrium receives de-oxygenated blood from the body through the superior vena cava (head and upper body) and inferior vena cava (legs and lower torso). The sinoatrial node sends an impulse that causes the cardiac muscle tissue of the atrium to contract in a coordinated, wave-like manner. The tricuspid valve, which separates the right atrium from the right ventricle, opens to allow the de-oxygenated blood collected in the right atrium to flow into the right ventricle.
Right Ventricle
Right Ventricle: The right ventricle receives de-oxygenated blood as the right atrium contracts. The pulmonary valve leading into the pulmonary artery is closed, allowing the ventricle to fill with blood. Once the ventricles are full, they contract.
As the right ventricle contracts, the tricuspid valve closes and the pulmonary valve opens. The closure of the tricuspid valve prevents blood from backing into the right atrium and the opening of the pulmonary valve allows the blood to flow into the pulmonary artery toward the lungs.
Left Ventricle
Left Ventricle: The left ventricle receives oxygenated blood as the left atrium contracts. The blood passes through the mitral valve into the right ventricle. The aortic valve leading into the aorta is closed, allowing the ventricle to fill with blood. Once the ventricles are full, they contract. As the left ventricle contracts, the mitral valve closes and the aortic valve opens. The closure of the mitral valve prevents blood from backing into the left atrium and the opening of the aortic valve allows the blood to flow into the aorta and flow throughout the body.
Aortic Valve
Aortic Valve: The aortic valve separates the left ventricle from the aorta. As the ventricles contract, it opens to allow the oxygenated blood collected in the left ventricle to flow throughout the body. It closes as the ventricles relax, preventing blood from returning to the heart.
Mitral Value
Mitral Valve: The mitral valve separates the left atrium from the left ventricle. It opens to allow the oxygenated blood collected in the left atrium to flow into the left ventricle. It closes as the left ventricle contracts, preventing blood from returning to the left atrium; thereby, forcing it to exit through the aortic valve into the aorta.
Left Atrium
Left Atrium: The left atrium receives oxygenated blood from the lungs through the pulmonary vein. As the contraction triggered by the sinoatrial node progresses through the atria, the blood passes through the mitral valve into the left ventricle.
Pulmonary Trunk
Pulmonary Trunk: A vessel that arises from the right ventricle of the heart, extends upward, and divides into the right and left pulmonary arteries that convey unaerated blood to the lungs. When the right ventricle contacts, the blood inside it is put under pressure and the tricuspid valve between the right atrium and ventricle closes. The only exit for blood from the right ventricle is then through the pulmonary trunk. The pulmonary trunk is to the right ventricle what the aorta is to the left ventricle – the outlet vessel.

What are heart valves?

The heart consists of four chambers, two atria (upper chambers) and two ventricles (lower chambers). There is a valve through which blood passes before leaving each chamber of the heart. The valves prevent the backward flow of blood. These valves are actual flaps that are located on each end of the two ventricles (lower chambers of the heart). They act as one-way inlets of blood on one side of a ventricle and one-way outlets of blood on the other side of a ventricle. Each valve actually has three flaps, except the mitral valve, which has two flaps. The four heart valves include the following:

  • tricuspid valve: located between the right atrium and the right ventricle
  • pulmonary valve: located between the right ventricle and the pulmonary artery
  • mitral valve: located between the left atrium and the left ventricle
  • aortic valve: located between the left ventricle and the aorta

How do the heart valves function?

As the heart muscle contracts and relaxes, the valves open and shut, letting blood flow into the ventricles and atria at alternate times. The following is a step-by-step illustration of how the valves function normally in the left ventricle:

  • After the left ventricle contracts, the aortic valve closes and the mitral valve opens, to allow blood to flow from the left atrium into the left ventricle.
  • As the left atrium contracts, more blood flows into the left ventricle.
  • When the left ventricle contracts again, the mitral valve closes and the aortic valve opens, so blood flows into the aorta.

What is heart valve disease?

Heart valves can have one of two malfunctions:

  • regurgitation
    The valve(s) does not close completely, causing the blood to flow backward instead of forward through the valve.
  • stenosis
    The valve(s) opening becomes narrowed or does not form properly, inhibiting the flow of blood out of the ventricle or atria. The heart is forced to pump blood with increased force in order to move blood through the stiff (stenotic) valve(s).

Heart valves can have both malfunctions at the same time (regurgitation and stenosis). When heart valves fail to open and close properly, the implications for the heart can be serious, possibly hampering the heart’s ability to pump blood adequately through the body. Heart valve problems are one cause of heart failure.