Hint - Flow of blood in the heart is unidirectional in both right and left part of the heart. This unidirectional flow is maintained by flaps like structure.Part 1 - Heart Heart is the blood-pumping organ that pumps blood throughout the body with the help of blood vessels of the circulatory system. The heart is divided into two halves: right and left. Both the halves have 1 atrium (upper chamber) and 1 ventricle (lower chamber) each.Part 2 - ValvesThe atrium and ventricle have valves in between the chambers to prevent the backflow of the blood.Between the right atrium and the right ventricle, the Tricuspid valve is present.Between the left atrium and the left ventricle, the Bicuspid valve is present.The semilunar valve is present between the ventricles and the pulmonary artery and the systemic aorta.Part 3 - ConclusionThe four valves present in the heart prevents the backflow of blood inside the heart.The thick muscular wall of ventricles (especially left ventricle) helps in sending blood to the entire body with pressure. The wall of atria is thinner than ventricles because they have to pump blood just to the ventricles and not to the body. Final step - The Valves in heart prevent the backflow of blood inside the heart.