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).
Overview. The human heart has 4 valves. The mitral valve connects the left atrium (LA) and the left ventricle (LV). The mitral valve opens during diastole to allow the blood flow from the LA to the LV. During ventricular systole, the mitral valve closes and prevents backflow to the LA.he human heart has 4 valves. The mitral valve connects the left atrium (LA) and the left ventricle (LV). The mitral valve opens during diastole to allow the blood flow from the LA to the LV.