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
The Heart String & How to Pull It 21 March and finishing on 8 April. Pledgers were offered various basic packages that included a physical copy of the album, a digital download of the album, a download of what became the "Chemicals EP", an album-themed T-shirt and an album-themed poster. All of the basic packages included the option to download the album a few days in advance of the physical release. Additionally, there were several special packages that were offered at premium prices. All of the special packages included a digital download of the album. The Heart String & How to Pull It The Heart String & How