Структура и заболевания сердца

12 ounces, beats 70 to 80 times a minute, and is enclosed by a sturdy membrane called pericardium.The four chambers of the heart have special roles in the pumping process.The upper chambers are called the auricles; the lower chambers, the ventricles.Between the right auricle and right ventricle is a valve, called the tricuspid valve.The valve action on both sides is also co-ordinated with the two phases of the pumping action.The weak walls of both auricles contract to press the blood into the relaxed ventricles.The mitral valve, between the left auricle and ventricle, has two cusps or leaflets.The tricuspid valve, between the right auricle and ventricle, has three cusps.Both valves function in the same manner.There is also a distinction between a heart attack, heart disease, and heart failure.