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.
There are four heart valves in a healthy human heart. The valves help to maintain proper blood flow through the heart, keeping blood moving efficiently and smoothly, and in the right direction. In addition to the valves there are four heart chambers -- the upper chambers are called the left and right atrium, the lower chambers are the left and right ventricle. A healthy heart valve will stop blood from flowing out of a heart chamber until it is time for the heart to pump the blood to its next destination.