The diaphragm separates the thoracic cavity containing the heart and lungs, from the abdominal cavity and performs an important function in respiration: as the diaphragm contracts, the volume of the thoracic cavity increases and air is drawn into the lungs.he superior surface of the dome forms the floor of the thoracic cavity, and the inferior surface the roof of the abdominal cavity. As a dome, the diaphragm has peripheral attachments to structures that make up the abdominal and chest walls.
A American Heart Association-Stroke Association answered. The four valves in your heart are made of thin (but strong) flaps (cusps) of tissue that open and close as your heart pumps. They make sure that blood flows through your heart in the right direction. Your valves work hard as they stretch back and forth with every heartbeat.
Blood moves through the four chambers as the heart pumps. There are four valves which control the flow of blood through the heart. They are called the aortic valve, the mitral valve, the pulmonary valve, and the tricuspid valve. With each beat, the valves open and close to keep blood moving in the right direction.