The US in now ranked 46th on the RWB list, in between Romania and Haiti. It was ranked 32nd in the 2013 index. The press freedom group was blunt in its explanation. It cited increased efforts to track down whistleblowers and the sources of leaks, mentioning Chelsea Manning and Edward Snowden in particular.
The heart has four valves-one for each chamber of the heart. The valves keep blood moving through the heart in the right direction. The mitral valve and tricuspid valve are located between the between the atria (upper heart chambers) and the ventricles (lower heart chambers).
There are four heart valves in a healthy human heart. The valves help to maintain proper blood flow through the heart, keeping blood moving efficiently and smoothly, and in the right direction. In addition to the valves there are four heart chambers -- the upper chambers are called the left and right atrium, the lower chambers are the left and right ventricle. A healthy heart valve will stop blood from flowing out of a heart chamber until it is time for the heart to pump the blood to its next destination.