___ are present to prevent backflow of blood in the heart.
Valves prevent backflow of blood from ventricles to atria when ventricles contract, and from the blood vessels to the ventricles when the ventricles relax.
________ are present to prevent backflow of blood in the heart.
Valves are present to prevent backflow of blood in the heart.
_______ are present in the heart to prevent backflow of blood within the chambers.
Valves prevent backflow of blood inside the heart during contraction.