Myocardium

• Myocardium

  • myocardium forms most of the bulk of the walls of the heart
  • is in between the epicardium and endocardium
  • endocardium is the layer of the heart wall closest to the heart chamber and surrounds the whole of the heart, part of the valves and the surrounds the whole of the cardiovascular system

  A) epicardium

  B) myocardium

  C) endocardium

  
• Myocardium:

  • consists of 3 types of excitable cells:
  • myocardial cells / myocytes (most common cell in the myocardium)
  • pacemaker cells - normally produce action potentials so orchestrate cardiac contraction
  • cells of the intrinsic cardiac conducting system (ICS) - help conduct the action potentials produced by pacemaker cells, across the myocardial cells