Conduction System

The fibrous skeleton is a dense framework of collagen within the heart that keeps the orifices of the atrioventricular (AV) valves and semilunar valve patent, provides an attachment site of the valve leaflets and cusps, serves as the origin and insertion sites of cardiac myocytes, and forms an electrical “barrier” between the atria and ventricles so that they contract independently.

The conducting system is made up of specialized myocardium (not nervous tissue)

Its fibres are finer than other myocardial fibres and are completely cross striated

Parts:
1. Sinoatrial node (SA node)
2. Atrioventricular node (AV node)
3. Atrioventricular bundle (of His)
4. Right and left branches of AV bundle
5. Sub endocardial Purkinje fibres

Blood supply:
Whole of conducting system except left branch of AV bundle is supplied by right coronary artery. In 40% cases, left coronary artery supplies SA node. 

The fibrous skeleton is a dense framework of collagen within the heart that keeps the orifices of the atrioventricular (AV) valves and semilunar valve patent, provides an attachment site of the valve leaflets and cusps, serves as the origin and insertion sites of cardiac myocytes, and forms an electrical “barrier” between the atria and ventricles so that they contract independently.

♣ The AV node is situated in the lower and dorsal part of the atrial septum just above the opening of the coronary sinus (within the Koch’s triangle)
♣ The SA node is situated in the wall of the right atrium in the upper part of sulcus terminalis just below the opening of superior vena cava

The fibrous skeleton is a dense framework of collagen within the heart that keeps the orifices of the atrioventricular (AV) valves and semilunar valve patent, provides an attachment site of the valve leaflets and cusps, serves as the origin and insertion sites of cardiac myocytes, and forms an electrical “barrier” between the atria and ventricles so that they contract independently.