Transport in animals

• Initiation/action of the heart muscle

  1. Electrical impulse originates from SAN and spreads across both atria causing them to contract. ( atrial systole )
  2. The impulse reaches the AVN where there is a delay, to ensure that atrial systole has been completed.
  3. AVN transmits impulse along septum through bundle of His until it reaches apex of heart.
  4. The Purkyne fibres spread around the ventricles and they carry the impulse along them, iniciating ventricle contractions