Cardiac conduction system: the conduction system composed of special myocardial fibers in the heart wall, whose function is to generate impulses and transmit them to all parts of the heart, so that atrial muscles and ventricular muscles contract according to a certain rhythm.

Composition of cardiac conduction system

Sinus node: produce excitement

Atrioventricular node: receiving or arousing excitement

Atrioventricular bundle: conduction excitation

Left and right bundle branches:

Purkinje fiber: the end is connected with the myocardium, causing myocardial contraction.

Pacemaker (sinoatrial node) starts the heart beating.

Sinus node produces electrical signals to start atrial contraction;

The atrioventricular node is the medium to transmit electrical signals to the ventricles.