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. At the start of each heartbeat, blood returning from the body and lungs fills the atria (the heart's two upper chambers). The mitral and tricuspid valves are located at the bottom of these chambers. As the blood builds up in the atria, these valves open to allow blood to flow into the ventricles (the heart's two lower chambers). After a brief delay, as the ventricles begin to contract, the mitral and tricuspid valves shut tightly.