AV Valves

Definition

The atrioventricular (AV) valves are one-way valves located between the atria and ventricles of the heart. They play a crucial role in the pumping action of the heart by ensuring the unidirectional flow of blood during the cardiac cycle.

5 Must Know Facts For Your Next Test

1. The AV valves open during ventricular diastole, allowing blood to flow from the atria to the ventricles.
2. During ventricular systole, the AV valves close to prevent backflow of blood from the ventricles to the atria.
3. The tricuspid valve has three leaflets, while the mitral valve has two leaflets.
4. The chordae tendineae attached to the AV valve leaflets help to maintain the proper shape and position of the valves during the cardiac cycle.
5. Dysfunction or disease of the AV valves can lead to conditions such as mitral valve prolapse, tricuspid regurgitation, or mitral stenosis.

Review Questions

• Describe the role of the AV valves in the pumping action of the heart.
  • The AV valves, consisting of the tricuspid valve and mitral valve, play a crucial role in the pumping action of the heart. During ventricular diastole, the AV valves open to allow blood to flow from the atria into the ventricles. This filling of the ventricles prepares them for the subsequent ventricular systole, where the AV valves close to prevent backflow of blood from the ventricles to the atria. The coordinated opening and closing of the AV valves, along with the contraction of the atria and ventricles, ensures the unidirectional flow of blood through the heart during the cardiac cycle.
• Explain the role of the chordae tendineae in the function of the AV valves.
  • The chordae tendineae are thin, tendon-like structures that connect the AV valve leaflets to the papillary muscles. They play a crucial role in maintaining the proper shape and position of the AV valves during the cardiac cycle. During ventricular systole, the contraction of the papillary muscles pulls on the chordae tendineae, preventing the AV valve leaflets from prolapsing or inverting into the atria. This ensures that the valves remain closed and prevent backflow of blood. The chordae tendineae, therefore, help to preserve the integrity of the AV valves and the unidirectional flow of blood through the heart.
• Discuss the potential consequences of AV valve dysfunction or disease.
  • Dysfunction or disease of the AV valves can lead to various cardiovascular conditions that can significantly impact the heart's pumping efficiency. Mitral valve prolapse, for example, can cause the mitral valve leaflets to bulge into the left atrium during ventricular systole, leading to mitral regurgitation and reduced blood flow to the body. Tricuspid regurgitation, on the other hand, can result in backflow of blood from the right ventricle to the right atrium, impairing the heart's ability to effectively pump blood to the lungs. Mitral stenosis, a narrowing of the mitral valve, can restrict blood flow from the left atrium to the left ventricle, reducing cardiac output. These AV valve-related conditions can ultimately lead to heart failure, pulmonary hypertension, and other cardiovascular complications if left untreated.

Related terms

Tricuspid Valve: The tricuspid valve is the AV valve located between the right atrium and right ventricle, allowing blood to flow from the right atrium to the right ventricle.

Mitral Valve: The mitral valve is the AV valve located between the left atrium and left ventricle, allowing blood to flow from the left atrium to the left ventricle.

Chordae Tendineae: The chordae tendineae are the thin, tendon-like structures that connect the AV valve leaflets to the papillary muscles, helping to prevent the valves from prolapsing during ventricular contraction.