The development of the atrioventricular node and bundle in the ferret heart

摘要: The development of the atrioventricular (AV) node and bundle in ferret heart was examined at light microscopic level. AV develops from two primordia which were first observed posterior wall common atrium during stage when single tube convolutes. During septation heart, nodal eventually fuse come to lie base interatrial septum. right primordium is located below attachment venous valve left maintains a position anterior prospective ostium coronary sinus. At 16 days gestation, large pale cells seen dorsal canal. By 21 gestation these canal have been replaced by cells. this time continuous with both primordia. birth mainly component that derived primordium. anulus fibrosus begins undergo greatest developmental change after attain their final junction. However, does not completely separate atria ventricles later stages nor birth, so accessory pathways are present newborn heart. Both also demonstrated continuity myocardial interventricular septum neonatal there no evidence rings specialized tissues junctions cardiac chambers give rise any conduction system.