Cuspid

... Not Really Sure ..... It maybe because atria does not have to pump blood anywhere but just to let me flow down into the ventricles when the tri/bi cuspid valves contracts...atria has more elasticity than ventricles but ventricles have thick walls....because they have to pump blood to the lungs/body ...

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the main valves r present between the atria & the ventricles the one between the right atria & right ventricle is the tricuspid valve & the one between the left atria & left ventricle is the bicuspid valve actually the valves look like they have leaflets thats y they are ...

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