Conducting System of Heart - Practice Questions & MCQ

Conducting system of the human heart 

• In human heart, small groups of specialised neuromuscular cells are present within the myocardium. 
• These neuromuscular cells initiate and conduct nerve impulses due to which a coordinated and synchronised contraction of the heart muscles is seen
• The components of conducting system of human heart includes sinoatrial node or SA node, Atrioventricular node or AV node, Bundle of His and Purkinje fibres

1. Sinoatrial node or SA node-

• It includes a mass of specialised self excitatory cells present in the wall of the right atrium near the opening of superior vena cava. 
• SA node is also called as the pacemaker of the heart because of its involvement in the initiation of heartbeat impulses
• SA node initiates impulses more rapidly than any other neuromuscular cells of heart.

2. Atrioventricular node or AV node

• It includes a mass of self excitatory tissue located in the wall of atrial septum near the atrioventricular valves. 
• Generally, it works on stimulation by SA node, but it is also capable of initiating its own impulses.
• It is also called as the pace setter of human heart

3. Bundle of his or atrioventricular bundle

• It is a mass of specialised fibres originating from AV node. 
• These separate atria from ventricles 
• At the upper end of ventricular septum, it is divided into left and right bundle branches

4. Purkinje fibres

• These are the fine fibres of AV bundle in the ventricular myocardium
• Both AV bundle and purkinje fibres convey impulses of contraction from AV Node to the apex of myocardium 
• Thus, AV node and purkinje fibres bring in ventricular contraction