Federal employees are compensated according to government-regulated pay scales. More than 70 percent of federal employees are paid according to the most common pay scale, the General Schedule (GS) , but there are a variety of alternative pay schedules as well.
Four heart valves control the flow of blood through the heart. They act as one-way doors, opening to let blood exit or enter a chamber, then closing to keep blood from flowing backward. 1  The tricuspid valve controls blood flow from the right atrium to the right ventricle.
Heart valves function to ensure a one-way flow of blood through the heart. The valves are not made of muscle, but rather are composed of sheets of tough connective tissue (leaflets) that act like flaps. The heart valves open and close passively because of pressure differences on either side of the valve.