Question

The first sound of the heart beat occurs during 1______, associated with the closure of 2_______, and 3______, The second sound of the heart beat occurs during 4_____, associated with the closure of 5______, and 6______.

• A. 1.Isovolumetric contraction 2.Mitral valve 3.Tricuspid valve 4. IsovolumetricRelaxation 5. Aortic valve 6. Pulmonary Valve
• B. 1.Isovolumetric Relaxation 2. Aortic valve 3. Pulmonary Valve 4. Isovolumetric contraction 5.Tricuspid valve 6.Mitral valve
• C. 1.Isovolumetric contraction 2.Mitral valve 3.Aortic valve 4.Isovolumetric Relaxation 5.Tricuspid valve 6.Pulmonary Valve
• D. 1.Isovolumetric Relaxation 2.Mitral valve 3.Aortic valve 4.Isovolumetric contraction 5.Tricuspid valve 6. Pulmonary Valve

Answer 1

The correct option is A

1.Isovolumetric contraction 2.Mitral valve 3.Tricuspid valve 4. IsovolumetricRelaxation 5. Aortic valve 6. Pulmonary Valve

The most fundamental heart sounds are the first and second sounds, usually abbreviated as S₁ and S₂. S₁ is caused by closure of the mitral and tricuspid valves at the beginning of isovolumetric ventricular contraction S₁ is normally slightly split (~0.04 sec) because mitral valve closure precedes tricuspid valve closure; however, this very short time interval cannot normally be heard with the stethoscope and hence only a single sound is perceived. S₂ is caused by closure of the aortic and pulmonic valves at the beginning of isovolumetric ventricular relaxation