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 More Years How Many More Years "How Many More Years" is a blues song written and originally recorded by Howlin' Wolf (born Chester Burnett) in July 1951. Recorded at the Memphis Recording Service – which later became the Sun Studio – it was released by Chess Records and reached no.4 on the "Billboard" R&B chart. Musician and record producer T-Bone Burnett has described "How Many More Years" as "in some ways... the first rock’n’roll song...". It was a double-sided hit with "Moanin' at Midnight", which reached no.10 on the R&B chart. After military service, Chester Burnett performed as a blues singer and