PARA104 Lecture Notes - Lecture 7: Depolarization, Defibrillation, Electrocardiography
Document Summary
It is important to remember that cardiac depolarisation starts with a single cell. As each cell depolarises, it triggers the surrounding cells are triggered and depolarise. This is how electrical currents generated in cardiac tissue. The conduction system of the heart comprises of 2 nodes and a conducting branch. These nodes are collections of cells that are specialised in producing and conducting action potentials. The electrical discharge for each cardiac cycle starts in the sinoatrial (sa) node) Depolarisation then spreads through the atrial muscle fibres. In a normal heart, the av junction is the only conductible pathway between the atria and the ventricles. This leads onto the bundle of his a highly conductible pathway which splits into the left and right bundle branches. The right and left bundle branches provide electrical stimulation to the ventricles. The smallest conduction branches are the perkinje fibres.
