What is the hearts structure?
The heart has four chambers through which blood is pumped. The upper two are the right and left atria. The lower two are the right and left ventricles. Four valves open and close to let blood flow in only one direction when the heart beats: • The tricuspid valve is between the right atrium and right ventricle. • The pulmonary or pulmonic valve is between the right ventricle and the pulmonary artery. • The mitral valve is between the left atrium and left ventricle. • The aortic valve is between the left ventricle and the aorta. Each valve has a set of flaps (also called leaflets or cusps). The mitral valve has two flaps. The others have three. Under normal conditions, the valves let blood flow in just one direction. Blood flow occurs only when there’s a difference in pressure across the valves that causes them to open. How does the heart pump blood? A heart’s four chambers must beat in an organized manner. This is governed by an electrical impulse. A chamber of the heart contracts when
