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.
How the heart valves work. 1  The mitral valve and tricuspid valve, which control blood flow from the atria to the ventricles. 2  The aortic valve and pulmonary valve, which control blood flow out of the ventricles.