The left bundle branch is located beneath the endocardium. It extends toward the middle of the left ventricle. It divides into smaller bundles and spreads throughout the left ventricle.
index-heart
Atrioventricular bundle
The atrioventricular bundle is a bundle of fibres that penetrate the fibrous body to conduct the electrical impulses from the AV node to the ventricles.
Atrioventricular node
The Atrioventricular node is a particular structure of cells located in the right atrium, somewhere near the centre of the heart, in a landmark known as the Triangle of Koch.
Sinuatrial (SA) node
The Sinuatrial node or SA node is shaped like a tadpole and is situated in the right atrium near the superior vena cava, in the terminal groove. Multiple interdigitations arise from the SA node, serving for a better connection between the node and the myocardium.
Subendocardial branches
The subendocardial branches or the Purkinje fibres continue the bundle branches like a mesh that lines the subendocardium. The Purkinje fibres interface with the working cardiac muscle cells.