Heart valve chambers are lined with endocardium. Heart valves separate the atria from the ventricles, or the ventricles from a blood vessel. Heart valves are situated around the fibrous rings of the cardiac skeleton. The valves incorporate leaflets or cusps, which are pushed open to allow blood flow and which then close together to seal and prevent backflow. The mitral valve has two cusps, whereas the others have three. There are nodules at the tips of the cusps that make the seal tighter. The pulmonary valve has left, right, and anterior cusps. The aortic valve has left, right, and posterior cusps. The
How Many Words How Many Words "How Many Words" is the official second single by the singer-songwriter Blake Lewis, from his debut album "A.D.D. (Audio Day Dream)". The song was expected to be followed by "Know My Name", and then "Without You". However, due to being dropped by Arista Records, "How Many Words" is the final single from his debut album. He is expected to release a single from his second album at the end of 2009. The single was released to mainstream radio format on March 10, 2008. Also, an EP featuring remixes of the song was released onto iTunes on May