‘Lub’ sound of Heart is caused by the___________.
- closure of the semilunar values
- opening of tricuspid and bicuspid values
- opening of the semilunar valves
- closure of the tricuspid and bicuspid valves
The Correct Option is D
Solution and Explanation
Atrial regurgitation is prevented by the closure of the atrioventricular valves (tricuspid and mitral) at the onset of ventricular contraction, producing the S1, or "lub," sound. The S2, or "dub," sound arises from the closure of the semilunar valves (pulmonary and aortic).
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(a) Right atrium receives oxygenated blood from lungs through pulmonary artery.
(b) Left atrium transfers oxygenated blood to left ventricle which sends it to various parts of the body.
(c) Right atrium receives deoxygenated blood through vena cava from upper and lower body.
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Select TRUE statements about lymph from the following:
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B. Lymph contains some amount of plasma, proteins and blood cells.
C. Lymph contains some amount of plasma, proteins and red blood cells.
D. Lymph vessels carry lymph through the body and finally open into larger veins.
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Name the blood vessel that brings (i) oxygenated blood (ii) deoxygenated blood, to the human heart. Also name that chamber of the heart which receives deoxygenated blood and state how deoxygenated blood from this chamber is sent to the lungs for oxygenation.
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