Conducting system of the heart:
Conductivity is the property by which the rhythmic electrical impulses generated are
conducted throughout the heart, causing rhythmic contraction of myocardium. Blood is
pumped into the great vessels during rhythmic contractions of heart.
It includes:
Sinoatrial node (SA node)-pacemaker of heart
Intermodal pathway
Atrioventrcular (AV node)
Bundle of his
Purkinje fibres
This system consist of specialized cardiac muscle cells that can initiate impuslses and
conduct them rapidly through the heart. Both atria contact together;and both ventricles
contarct together. The atrial contarction occurs first. The synchronized contraction of the
chambers is essential for the efficient pumping of heart and for the maintenance of systemic
and pulmonary circulations.
SA node is situated in right atrium just below the opening of superior vena cava. AV node is
situated in right posterior portion of Intra-atrial septum. The impulses from SA node are
conducted throughout the right and left atria. The impulses also reach the AV node via some
specialised fibres called intermodal fibres. There are three types of intermodal fibres:
1.Anterior internodal fibres of Bachman
2.Middle internodal fibres of weckbebach
3.posterior internodal fibres of Thorel.
All these fibres from SA node converge on AV node and interdigitate with fibres of AV node.
From AV node, the bundle of his arises. It divides into right and left branches which run on
Conductivity is the property by which the rhythmic electrical impulses generated are
conducted throughout the heart, causing rhythmic contraction of myocardium. Blood is
pumped into the great vessels during rhythmic contractions of heart.
It includes:
Sinoatrial node (SA node)-pacemaker of heart
Intermodal pathway
Atrioventrcular (AV node)
Bundle of his
Purkinje fibres
This system consist of specialized cardiac muscle cells that can initiate impuslses and
conduct them rapidly through the heart. Both atria contact together;and both ventricles
contarct together. The atrial contarction occurs first. The synchronized contraction of the
chambers is essential for the efficient pumping of heart and for the maintenance of systemic
and pulmonary circulations.
SA node is situated in right atrium just below the opening of superior vena cava. AV node is
situated in right posterior portion of Intra-atrial septum. The impulses from SA node are
conducted throughout the right and left atria. The impulses also reach the AV node via some
specialised fibres called intermodal fibres. There are three types of intermodal fibres:
1.Anterior internodal fibres of Bachman
2.Middle internodal fibres of weckbebach
3.posterior internodal fibres of Thorel.
All these fibres from SA node converge on AV node and interdigitate with fibres of AV node.
From AV node, the bundle of his arises. It divides into right and left branches which run on
