Heart 8 around the two ventricles and proceeding toward the apex. This complex swirling pattern allows the heart to pump blood more effectively. There are two types of cells in cardiac muscle: muscle cells which have the ability to contract easily, and pacemaker cells of the conducting system. The muscle cells make up the bulk (99%) of cells in the atria and ventricles. These contractile cells are connected by intercalated discs which allow a rapid response to impulses of action potential from the pacemaker cells. The intercalated discs allow the cells to act as a syncytium and enable the contractions that
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