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.
The valves of the heart serve the cardiovascular system by controlling the direction of the blood flow during circulation and determining the exact moment in which the blood passes between the chambers of the heart as well as in and out of it entirely.