Electrical control

• Electrical control:

  Atrial systole

  • Sinoatrial node (SAN) at the top of the right atrium releases the wave of excitement that travels through the atrium walls and valves
  • This causes the atria to contract

  
• Electrical control:

  Delay between atrial systole and ventricular systole

  • A layer of non-conductive connective tissue between the atria and ventricles prevents the wave of excitement spreading.
  • The electrical impulses reach the Atrioventricular node (AVN) which delays the wave of excitement and allows the atria to fully contract before the ventricles start to contract
• Electrical control:

  Ventricular systole

  • Atrioventricular node (AVN) releases the wave of excitement.
  • It travels down the septum through highly conductive tissue called the Bundle of His to the apex of the heart
  • It the travels through the walls of the ventricles in the Purkinje fibres

  
• Electrical control:

  Diastole

  • The wave of excitement reaches the non-conductive tissue and is terminated