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.
These are the only valves in the heart. There are four valves in the heart (not counting the valve of the coronary, the isotonic valve and the valve of the inferior vena cava): two atrioventricular valves (mitral valve and tricuspid valve); and two semilunar valves (aortic valve and pulmonic valve).