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.
The mitral valve regulates the flow of oxygen rich blood from the lungs to pass from the left atrium to the left ventricle.There are two main diseases or malfunctions of heart valves: regurgitation (valve does not close tightly) and stenosis (valve does not open fully).itral Valve Regurgitation, Stenosis, and Prolapse. The mitral valve is referred to as atrioventricular valves because it is located between the left atria and the left ventricle.