MCQ
What prevents backflow of blood inside the heart during contraction?
- ✓Valves in heart.
- BThick muscular walls of ventricles.
- CThin walls of atria.
- DInner lining of the heart.
✓
Answer
Correct option: A.
Valves in heart.
Valves ensure that blood does not flow backwards when the atria or ventricles contract. Semilunar valves, the valves present between ventricles and their attached vessels, serve to prevent the backflow of blood to ventricles from their respective attached vessels. Likewise, atrioventricular $\ce{(AV)}$ valve between atrium and ventricle directs the flow of blood and prevents any backflow into atria.
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